NOTE: Got some info today regarding the accuracy penalty to Mass Hypnosis - apparently there isn't any, anymore. Stupid Hero Planner! But, hey, this is a good thing!
Revised slotting for MH: 1 acc; 3 sleep, 2 recharge
And BTW - as for Telekinesis, one could easily swap out TK Thrust for Telekinesis, and move 2 of the health slots from Drain Psyche and put them into Telekinesis (and slot it with 3 end reductions). Telekinesis is an amazing power (it's just not for me).
I would make these edits to the post itself, but apparently I've exceeded my max edit amount. 
A nice guide and worth bumping to note that Issue 7 *does* finally allow accuracy enhancements in Drain Psyche, which according to the notes it should have always had (only seven months for that fix :P).
Completely agreed on Mental Blast. Fixing the animation time on it is apparently a real low priority and without a fix, it's one of the worst blast powers in CoV/CoH.
I've earned a respec and am mulling over what to change. I was originally going to get stamina but find that between Catch a Breaths and Drain Psyche, I've managed decently so far (I only took Swift then focused on powers outside the Fitness pool). I picked up Total Domination but the recharge time and hold duration make it pretty much useless, in my opinion.
I also use Telekinetic Thrust as a guilty pleasure. It's just so fun to fling enemies around with it. 
It has practical application for positioning, too.
Again, good guide. Thanks for taking the time to write it.
Looks like a decent build with the exception of SS. I personally don't like SS because without hurdle travel can be a pain. SJ and flight are my two favorites and I usually only use SJ for brutes.
I most likely will take flight but can you quickly explain why you chose SS. Just curious 
I would assume he took SS to stack with Stealth to get near complete invisibility.
It's a really usefull combo to set up PBAOEs and Cone attacks or to just stealth/scout missions.
Centinull
I recently respec-ed my Mind/Psi Dom and am very pleased with the results. What I did is very telling, though.
I was trying to take all the primary and secondary powers to make myself familiar with them. Turns out a Mind/Psi with only his primary and secondaries performs horribly even when teamed, as I do almost exclusively, with a stalker.
I dispensed with Telekinetic Thrust (my nomination for Worst Power Ever,) Mental Blast (infamous) and Psychic Scream. I also ditched Mind Probe as I decided to stick with a completely ranged Dom at this point.
These I replaced with the Fitness line and Assault-Tactics. And suddenly my Dom was acceptable. Not great, but acceptable.
Currently my Dom will be investing in all the Mind Control powers except Total Domination, and only Drain Psyche, Subdue and Psi Shockwave from the secondary. I've also slotted Psi Dart with a reduced End and a Recharge to build Domination quickly.
In sum, Pool Powers are a much better investment than the frighteningly bad initial powers in Psi Assault.
How a Mind/Psi will possibly measure up in PvP against a Mind/_ Controller or a _/Psi Defender... I can't begin to imagine.
Now, I use mental blast as a filler spot till I get Psychic Lance. Saving that respec for that. My travel power for him tho is teleport.
Well, with Issue 8 Mental Blast suddenly became MUCH more attractive, I haven't done any really heavy testing with it, but it feels like about twice the activation of Psi Dart now (which seems to mesh with other reports on it). Anyway, I'm working a Damage Only Psy concept, which skipped Mass Hypnosis, Confuse, and Telekinesis (Three counts of HERESY! I know... 
)
I've noticed that without running any of those fancy tricks and focusing purely on DPS, I can't seem to run out of endurance in the amount of time it takes to build to full Domination. Now that I have a few vet respecs, I'm going to copy my Dom to test and try out a whole slew of other builds to see if I find anything better, but currently, my Damage Only concept is quite enjoyable.
All that is planned fails. All that is born dies.
All that is built crumbles. This will always be true.
But memories remain, And that is beautiful.
My main complaint with mind/psi is that while I can lock down huge amounts of stuff (especially with hasten running) my damage output is very low. I'm playing with the slotting a little there, and now that I have SO's I'll be backing off on twin acc on attacks (I hate missing).. A few notes..
1) I like slotting some sleep durations on the basic mez, probably not that critical for a team situation where people always wake them anyway but for solo play it lets me juggle a larger number of balls at once.
2) TK thrust rocks.. Some here have called it worst power ever, but frankly that's not been my experience. yeah to a degree it's a total guilty pleasure due to the animation. but there's some real utility to it.
a- great as a single mob delaying tactic. during initial lockdown phase. If a hold misses, or something runs up to you, and both Mez and Dom are recharging, use Thrust to buy a little time, before they've picked themselves up, one of the real holds is usually recharged and you can lock em down.
b- the greater utility however is that it's also highly useful for moving mobs around. getting low on end? mobs all spread out? hit one with your hard hold (Dominate) place yourself accordingly and THRUST them where you want them to go.. apply a sleep, wash, rinse, and repeat until you've assembled a nice little pile of sleeping zombies, and then kick off drain Psyche. and get a fillup. This is great for those darned missions where stuff is on two sides of the hall, and too spread out to get an effective drain on them.. or to keep all stuff in view so you know who's under and who needs mez or dom love.
c) gets my vote for best stylistic finishing move of any of the sub 22 powers.
3) Hasten is IMHO a must.. when you really got to work fast to lock down a bunch of stuff, or when you need to stack rapid repeated holds to lock down a boss, or psy-resistent mob, hasten really helps.. Also helps you to spam those attacks when you need to rebuild domination.. or along with domination, and drain psyche, it's near god mode for a few minutes.
I'm amazed that the psi attack set is so weak, especially compared to what defenders get! but it is poorly resisted by most things, and it's fast and fairly low on the end.. so it can be made to work.
with set IO's hasten as a requirement is a thing of the past for mind/psi doms. The way things are shaping up, mass confuse+drain psyche+psychic shockwave=more dead mobs than a fire-kin on acid.
This guide is current through issue 6.
. It can be useful if a held or confused target is not where you want him TK Thrust him where you want him to go (if hes confused, you can thrust him into a group of enemies so he can attack them). And it also has a -fly effect, so it can knock annoying flying targets out of the sky (but since it's a melee attack, heh, it depends how high up they are). 1 accuracy is sufficient.
. A more practical slotting would be: 1 or 2 end modifcation and 1 or 2 recharge.
Build:
Mind Control:
Mesmerize (acc) (dmg) (dmg) (dmg)
Dominate (acc) (hold) (hold) (hold) (rech) (rech)
Levitate (acc) (dmg) (dmg) (dmg)
Confuse (acc) (conf) (conf)
Mass Hypnosis (acc) (acc) (sleep) (sleep) (sleep) (rech)
Terrify (acc) (fear) (fear) (fear) (to hit deb) (to hit deb)
Mass Confusion (acc) (acc) (conf) (conf) (conf) (rech)
Psi Assault:
Psi Dart (acc)
Mind Probe (acc) (dmg) (dmg) (dmg)
TK Thrust (acc)
Drain Psyche (endmod) (endmod) (endmod) (health) (health) (health)
Subdue (acc) (dmg) (dmg) (dmg)
Psionic Lance (acc) (dmg) (dmg) (dmg)
Psychic Shockwave (acc) (dmg) (dmg) (dmg) (rech) (rech)
Hasten (rech)
Super Speed (run)
Stealth (end red)
Swift (run)
Health (health)
Stamina (endmod) (endmod) (endmod)
Power Explanations - Mind Control:
Mezmerize single target sleep. It has a magnitude of 4 meaning, one application of it can one-shot-sleep just about any enemy including bosses (short of an AV/Elite Boss) in the game. It is a great way to help stack your single target hold on a boss dominate/mezmerize/dominate it reduces the return fire you will get from him because he will be slept while dominate recharges (although he will probably get a hit on you between the first application of dominate and the mezmerize). Drawback its a sleep, so any hit on the sleeping enemy will break the sleep. However it has a very long base duration (34 seconds on a typical 1+ yellow minion), and it recharges faster than dominate (your single target hold). It is also highly accurate (it has an accuracy bonus). It also doesnt cost much endurance (6 points per). It does NOT take recharge enhancements. It also does moderate damage in the ballpark of /psis single target moderate damage attack mental blast. You could, literally, mezmerize an enemy to death. Keep in mind, however, that an enemy that is sleeping sometimes wakes up for a split second when you reapply mezmerize and will attack you once. I slotted it 1 acc, 3 damage. This way, it functions really well as an accurate, long duration sleep that adds to my DPS.
Dominate single target hold. It is your single target hold, and as such is the single most-important power to any dominator. It has a magnitude of 3 meaning, one application of it can lock down anything except for a boss (which will need 2 applications of it to hold him). It has a shorter base duration, longer recharge, but higher accuracy bonus, than Mezmerize. It also does about the same amount of damage (moderate). This power deserves 6 slots I would go with 1 accuracy, 3 hold durations, and 2 damage use it as an all-purpose hold-plus-attack. Slotted this way, it will do almost the same damage as Mezmerize, and add to your DPS. Once you take Subdue from the /psi secondary (available at level 28), I would change the slotting of dominate to 1 acc, 3 hold, and 2 recharge since Subdue will significantly increase your damage output. 2 recharges will allow you to stack holds on bosses much faster, and help you to spam the hold on more enemies more often. If you do a lot more teaming up than soloing, I would forego the 2 damage slotting and put the 2 recharges in there instead and use it strictly for its hold function.
Levitate single target knockup/knockdown attack, and a must (at least for a /psi dominator). This power is great as a ghetto hold since it lifts the target into the air, and onto the ground (he has to pick himself up): meaning, it preoccupies the enemy for a few seconds because it has a knockdown/knockup effect. This is yet another way to help you stack dominate (your hold) on a boss dominate/levitate/dominate it reduces the return fire you will get from him because he will be lifted and falling and picking himself up while dominate recharges. Its also great for pulling an enemy because hes lifted and then slammed, you will have plenty of time to run around a corner. This power is a must for /psi dominators because it has psi AND smashing damage which can be a godsend when you are fighting enemies that resist psi damage (like robots). It does medium damage above mesmerize and mental blast, but less than mind probe and subdue. This power has no accuracy bonus, so it will miss more frequently than dominate or mesmerize, so I would slot it with 1 accuracy, and maybe add a second accuracy for good measure if you really hate to miss. 1 acc 3 damage is a standard attack slotting.
Confuse single target confuse. This power makes enemies attack their buddies and not you. Meaning, this power is yet another way for you to neutralize threats. Even better, you convert them into your pets they will not only attack their buddies (or inanimate objects that need to be destroyed like bank vaults), but they will buff/heal you and your friends. Confusion is my favorite and perhaps the safest way for you to stack holds on a boss: stack confuse on a boss from a distance (no aggro) let him kill whoever is near him then when hes alone and still confused, you can stack dominate on him without him attacking you at all. This power, along with levitate, can help you get through tough solo missions where the enemies are resistant to psi damage. This power does not, alone, produce aggro. Meaning, if you use it from far away, the target and his buddies (whom he will attack and perhaps kill) wont come after you when it wears off (or if it misses). Also, if you confuse a boss who has a pet (or pets), those pets will ALSO be confused if he is meaning, if the Family Boss has a singularity hovering over him, once you confuse him, his singularity will also instantly be confused and they will attack each other (NEVER use confuse on a pet use it on the boss and confuse them both at once). A great way to use this power to open a fight is to confuse the most dangerous target, or a target that has healing/buffing/control powers, from a distance and then engage them that target will be your pet for the fight. But the confused enemy will not follow you and fight at your side he will only attack whatever is near him (in aggro range). If you have TP foe you could bring him along with you wherever you go. Confuse also is a TON of fun to mess around with you will have favorite enemies to use this power on such as Family bosses that have a singularity pet out which produces some hilarious, uplifting (pun!) visual effects. Or Tsoo Sorcerers want a heal? You got it! Or Rikti guardians want a bazillion, stacked shields on you? You get the idea. Downside it had to have a downside, right? The longest animation time in the game. It will seem totally crazy its 6 seconds. When it misses and you are trying to stack it on a boss it has a magnitude of 3 so it wont confuse a boss with just one application it can get frustrating. For that reason, confusion duration enhancements are required. It has an accuracy bonus, so 1 accuracy, 2 confuse durations allows me to hit often, and lets it last long enough for me to stack 2 applications of dominate on any boss in complete safety. 1 accuracy, 3 confuse, and 1 recharge would be ideal, though, if you can spare the slots.
Mass Hypnosis This power, while a sleep with a shorter base duration than mesmerize, affects up to 10 targets at once and has many uses. It, like confuse (and mass confusion), is completely aggro-free. Use it to prevent the alpha strike: when you approach a group, use MH, and they will all be slept. At that point, you (or your team) can pick and choose which targets to attack first, without getting hammered by all of them at once. Use it to thin a nasty group: MH the group, then snipe an enemy of choice from that group he will wake up, come running for you finish him off and repeat on another enemy from the group. When they wake up, they wont have noticed that their buddies are missing. Use it to stop ambushes: which always seem to happen once your team has engaged another group ahead of you you hear on broadcast, Get Player X! and know that they are coming from behind. Turn around, and when they get near, use MH on them. This will stop them dead in their tracks, and give your team time to finish off the first group. Use it to stop accidental, unwanted aggros: if you are fighting a group and a second group gets aggrod accidentally, run up to them and use MH on them it will keep them out of the fight for quite awhile. Use it in the heat of battle (who cares!): yeah, its a sleep, so anyone can break it with an attack. But anyone who hasnt been lobotomized will realize that an attack will wake the enemy up, and they can decide for themselves when to attack those slept targets. You will be surprised how many times, in the middle of a huge fight, an enemy will be sleeping, while the brutes and stalkers are hammering on their buddies right next to them. It has a penalty to accuracy, but Ive found 2 accuracy enhancements to make it very reliable. It also recharges fast enough to allow it to be up almost every fight 45 seconds. Functional slotting: 2 acc, 3 sleep duration, 1 recharge.
Terrify a (large, deep) cone fear power that has a nice base duration, fast recharge (40 seconds), deals moderate damage (on par with mezmerize and dominate), and has an accuracy debuff effect on enemies, this power is useful in teams. With a couple of recharges and fear durations, it can be perm-able. It will be very useful because terrified enemies dont attack unless you hit them first. But it has drawbacks for one, it does damage so it draws aggro to you and if you are using it on a large team against a huge group it can get you faceplanted because the enemies typically blast you once before the fear effect kicks in. 8-10 enemies blasting you once adds up in a not-so-nice way. Also, Ive found that even if a teammate hits a terrified enemy, the enemy will initially shoot at ME rather than my teammate who just hit HIM at least until my teammate hits him a second time! Meaning, if you use this power on a large group, break line of sight on as many of the terrified enemies as soon as you can. Also, feared enemies dont turn into statutes they can randomly decide to pick up and run for a bit which means you will have to chase them down. I only took this power as another Oh noes! panic control power because I have so many other tricks up my sleeve that I like better (Im usually busy using the above powers and mass confusion), I can count on one hand the number of times Ive used it solo. But I do use it when teamed. Because my health bar seemed to always pay a big price for its use when fighting large groups, I slotted it with 1 accuracy, 3 fear, 2 to-hit debuffs but 2 recharges instead of the to-hit debuffs can make this power perma.
Mass Confusion this is it, the power you have been waiting for. Unlike confuse, it is a group-confuse power, but without the ridiculous animation time. Like confuse, it will turn all affected enemies into your pets. It will turn a roomful of enemies into a riot they will devour themselves in no time flat. Like confuse, it does NOT draw aggro onto you, so enemies wont attack you when the effect wears off or if you miss (provided, of course, you aren't in aggro range when the confusion effect wears off). It can be fired from a distance, like confuse. You can use this power to stack confusion on a boss very quickly use confuse, then fire mass confusion, to pass his magnitude quickly (Mass Confusion has a magnitude of 3). Any enemies that defeat each other without any damage input from you or a teammate won't give you xp - so you should get at least one hit on every confused enemy if you can (psychic shockwave and/or psychic scream can help with this - see below). This power has a long recharge, however 240 seconds so use it wisely. I use this power as my panic control power since it will help make any nasty surprise group eat itself alive (far more effective, IMO, than terrify), or for the main boss fight at the end of a mission with domination running, Mass Confusion is wickedly powerful. I have it slotted 2 accuracy; 3 confusion; 1 recharge. I also hit hasten right after using it to help it recharge faster.
Powers I skipped:
Total Domination. Like all dominator AoE holds, it has a hefty accuracy penalty, very very very short hold duration, and preposterously long recharge time (relative to its duration). It needs 6 slots (2 accuracy, 2 hold, 2 recharge) to improve its status from HORRID-OMG-I-NEED-TO-RESPEC-OUT-OF-THIS-NOW, to Crappy. Terrify and Mass Confusion are more useful as panic control powers than TD.
Telekinesis. I am definitely going against the grain here, because Telekinesis is arguably the signature power of any mind/ dominator (or controller). But it is just way too tricky for me to use it effectively I always screwed it up so I didnt take it. It is unlike any power in the game it lifts a target into the air and propels him slowly backward, and any enemies he gets near are also lifted up and propelled backwards. Problem for me is they KEEP floating backward, and unless you can position yourself to propel the target into a wall, you will lose them and possibly aggro other mobs. Used properly, it is an amazing power. I didnt have patience to explore its potential (I hate cone powers or powers where you need to position yourself just right bah!). It also has an intense endurance drain so stamina is a MUST if you plan on taking this power, and 3 endurance reductions on it is also recommended.
Power Explanations - Psi Assault:
Psi Dart minimal damage, but really fast recharge and low endurance cost and fast animation time. Drop 1 accuracy enhancement in it (or 1 endurance reduction if you dont have stamina OR drain psyche) and spam it to build domination.
Mind Probe one of the highest damaging attacks in the /psi assault set, it is a must. It is described as having moderate damage, but its more like high damage it does more than levitate. It is a melee attack, but has quick animation and delivers nice damage. Since you have to get into melee range, only use it once your enemy is held or confused. Slotting is standard 1 acc, 3 damage.
TK Thrust a guilty pleasure and definitely skippable, it is a melee-knockback attack. It does minor smashing and psi damage. Its great if you have an enemy right in your face because its highly accurate and will send them flying. But levitate makes this knockback power redundant (and is safer because you can achieve knockup/knockdown at range), and does way more damage. In other words, as a mind/ dominator you have so many control tricks up your sleeve that you dont need a ghetto hold or soft control that this knockback power provides. But I like it because it has a really cool sound effect and animation and when an enemy has a sliver of health left I use it to finish him with a dramatic flourish
Subdue its mind probe-level damage (described in the game as doing moderate damage, but would be more accurately described as doing high damage), but ranged. And oh, yeah it has an immobilization secondary effect. Once you get this power, at level 28, which you must do, you can kill enemies entirely at range if you so choose. 1 accuracy 3 damage should be your slotting.
Drain Psyche the wildcard power in the /psi deck because it doesnt take accuracy enhancements. It reduces an enemys endurance and health recovery and boosts your own for 30 seconds. It has a very short PBAOE range just a bit longer than melee range. If you are planning on taking stamina, you wont need this power. Now, the big question everyone wonders when looking at /psi: do you need stamina if you take drain psyche? Mind/psi is fairly light on endurance, so it is possible, in theory, to get by on Drain Psyche and skip the fitness power pool altogether. Ive tried it without stamina and if it hits just one enemy, the endurance recovery is noticeable (it works, after connecting on just one enemy, as a kind of conserve power if you are fighting). If it connects on more than one enemy, the recovery is tremendous (approaching recovery aura from the defender set). Plus, when you hit domination, your endurance bar completely fills, anyway. But without accepting accuracy enhancements, this power will miss, so it is nowhere near as reliable as stamina. Also, it lasts 30 seconds, which, again, means it is not as consistent as stamina. If and when this power does accept accuracy enhancements (which might happen with issue 7), then skipping stamina would be more viable. There are powers later on in the mind/ set that can be endurance drains (mass confusion and terrify). Also, if you take telekinesis, and have drain psyche instead of stamina, DP has to connect or else you will be eating endurance inspirations like crazy whenever you use telekinesis. I dont like messing around with my endurance, so I took stamina and dont rely on DP. But I picked it up thinking, if it hits, great, if not, who care because I have stamina, and thought it would be fun just to mess around with. Because I dont depend on it for my endurance recovery, I really have enjoyed using it its great as a downtime-reducer. Always use it when there are at least 2 enemies near you preferably more if possible: if there are at least 2 enemies, it will more often than not connect on at least one of them. It is great against an Elite Boss (to hold down on his health recovery). It is amazing in a large group where there are a ton of enemies grouped tightly together because it will hit several enemies. And, it does NOT break any sleep so you could use Mass Hypnosis on a group, run in and use DP on them, then engage them. The health recovery is also pretty nice. With this power and stamina and domination, it is overkill: I never, ever have to slot for endurance reductions on any power. I have it slotted 3 end mod; 3 health. Note: I 6-slotted this power because slotted this way and activating both it AND domination is the equivalent of playing in near-God mode, which I get a kick out of, and allows me to thumb my nose at the ED nerfs
Psionic Lance a sniper attack, it is the highest-damaging attack in the /psi set. It has the issues of any sniper attack it is interruptible, and has a long activation time (about 4 seconds). Sure, it takes awhile to activate, but the payoff, the damage is worth it. In teams I use it to help finish off the boss or last standing enemy that everyones beating up on (Ive seen it do the same amount of damage as a brutes fury-boosted attack), and solo, my targets are controlled, so I rarely get interrupted. It halves a typical +1 yellow minions health. I rarely use it to pull I use it in my attack chain, firing off all my faster-recharging attacks first, and using this as a finishing move, or to do great damage while those attacks recharge (on a boss, for example my other attacks will have recharged once the snipe has fired). And being a snipe, it has a great accuracy bonus so it RARELY misses. Slotting: 1 accuracy, 3 damage
Psychic Shockwave this is it the attack power youve waited for, and one of the best in the game. It is PBAoE, and its radius is surprisingly large much larger than melee range. Its like a mini-nuke, but it only costs 10 endurance to fire and has a 10 second recharge. It does high damage up there with mind probe and subdue. Plus it has a chance to disorient (on par with bone smasher from the /nrg set). Absolutely worth the wait. With domination running, its damage is even better. On a mass-confused mob, you will rip them to pieces in no time. It has a cool sound effect, as well. 6 slot this power 1 acc, 3 dmg, 2 rech (disorient duration enhancements arent needed because the disorient side effect isnt reliable, and you have a ton of more effective control options, so the disorient should just be a nice bonus effect).
Powers I Skipped:
Mental Blast long animation time about 3-4 seconds from the time you activate the power until it finally travels to its intended target and inflicts damage. Its activation time is on par with psionic lance, but it does 3 times LESS damage than lance, so if you're thinking of taking either/or, take lance. Mental Blast is okay at lower levels if you are desperate for another attack, but definitely respec out of it once you get subdue (which does more damage and has a shorter activation time). Rumors are that the devs will be improving the animation of mental blast if so, it might make the power more attractive.
Psychic Scream again, this is just personal taste, but I dont like cone powers, and this is a narrow cone attack power that does moderate (on par with mental blast or mesmerize) damage. But it costs more endurance because its a cone, and has a longer recharge time. It can be really effective though, especially if needing to get a hit on a group of mass confused enemies that are tearing each other apart really quickly. But thats what Psy Shockwave does for me, and it does way more damage (and has a nice disorient side effect). One could easily swap this power with Psionic Lance. Psy Shockwave outdamages and outclasses psychic scream, IMO, and I just didnt need both of them for my playstyle.
Power Pools:
Hasten this power can really help a /psi dominator increase his DPS on that end-of-mission boss who needs to be taken down while domination is running (in other words, while you are still safe). Its also a great panic button when things get nasty, its like throwing 2 recharge SOs into all of your controls and attacks, which can really help turn things around. And I use it right after I use Mass Confusion, to help improve its recharge time. Very situational, but really handy.
Super Speed I love using it to zip through missions quickly, as a scouting tool.
Stealth Since you are squishy, this is a great way to cut down on surprise, accidental aggro, and to help keep yourself safe when getting around in the main zones.
Swift great to help you get in and out of melee range quickly (or lining up cones bleh) when using mind probe and drain psyche. Stacks with super speed to help you travel faster.
Health helps cut downtime but is just a stepping stone for stamina.
Stamina if and when drain psyche accepts accuracy enhancements (possibly in issue 7), and provided nothing else about drain psyche changes (to balance it for the accuracy enhancements), I will be dropping stamina. Until then, its a safe and practical pick.