Short answer: no
Explained answer: If u already got PSW, u just have to use it again and again to rocket ur dps...
So, IMHO, u should just get from ur secondary Mind Probe, Drain psiche, Subdue (for runers) and PSW...
Ive heard that ppl has a lot of -rech and has achieved to fire PSW each 3 secs... THAT is powerfull.
A build?? I would go:
grav: lift, gd, gdf, wh, sing.
psi: dart, mp, drain psy, subdue, PSW. (maybe sniper if u are lookin for nice -rech, since it can get 7.5% recharge)
pools:
hurdle, health, stamina
hasten
combat jumping, super jump
These are the core powers, u can get a KB IO and avoid acrobatics (i preefer waste a few mills instead of losin a power selection, that also consumes end), u can get leadership if u want to, or go to medicine, or get fightin for tough, or whatever...
This is the way i see dominators works better...
I took mental blast and psy scream on my domi before i hit 38. Then after that, I specced them both out. Mind Probe and Subdue are all the space you need inbetween PSW really. Mind probe is a great attack, and as your most likely to be in melee range to use PSW, its great to have. Subdue helps with the runners and is a nice attack too. When you have hasten and some +rch bonuses, PSW comes back up at an insanely fast rate for the damage it does.
So MB is worth taking for the pre PSW lvls, but after that, well unless you dont plan on taking PSW, (and if you dont, why did you bother making a /psi domi?) its just not needed unless you exemp an awful lot or want extra fire power vs Hami in the LGTF.
Hmm, interesting replies. I wasnt going to get into build discussion, but I may as well. A few thoughts then.
It was never a question of whether to take PSW or not. Its a no brainer. As my main AE tool, it rocks.
Still, single mobs do happen, and I dont particularly want to be using PSW on a single mob. Its not hugely uneconomical, but its not great either. On single mobs it's also overkill.
In addition to PSW, I wanted an unbroken attack chain. I had Air Sup, which is a solid attack with a nice knockdown, but if possible I wanted to keep it PSI. Now, thats not just for concept but for the recharge. If we dont use powers that complement each other, then they become weaker individually. Dart, blast, PSW, Scream and Probe are laden with the recharge secondary. Ive had them stacked on me, and know how bloody irritating it is.
Dart, Probe, Blast and Subdue allows me to chain in melee and at range against a single mob, and also do the whole PSW I kill mobs by the dozen act. Best of both worlds.
I have swift, Health and Stamina in my current build, and will be respeccing out of them. With Drain Psyche and Power Sink slotted for recharge, there is simply no need for them. I used to get by fine with just Drain Psyche. With power sink as well, they will both be slotted to a 60 second recharge even with regular IOs, so I can pop one every 30 seconds more than enough. I wanted to be sure so I tested this on the test server and it holds up very well. Having stamina in that scenario is massive overkill. I dont miss Health or Swift and Hurdle seems a waste of space if I dont go super speed.
So it comes to the point where you think, what else is there to take? I dont really need much else.
This is where Ill be at if I go ahead:
Grav: Lift, GD, GDF, Crushing Field, Worm, Sing and yes I am keeping Dimension Shift. Its too useful to drop and doesnt need extra slotting.
PSI: Dart, Mind Probe, Telekinetic Thrust, Mental Blast, Psi Scream, Subdue, Drain Psyche, PSW.
Reasons:
GD and GDF are the obvious ones, as is Sing. Wormy goes with Crushing field quite nicely and Lift is still useful as a ghetto. Dimension Shift Im a big fan. Use it constantly solo, and its a team saver. I cant imagine my build without it.
The two grav Ill be leaving out is propel and the single target immo, Crush. One is too slow, and the other is superseded at lower levels by Lift.
Dart, Probe, Blast and Subdue are my melee range chain. Remove probe for the range chain. Scream and PSW are of course my AE set to go with Wormhole. TK thrust for the same reason I use Lift - ghetto times 2. (Also it rocks for pushing mobs back into that corner where you are dropping PSW)
The only PSI I wont be taking is the snipe, PSI Lance. Dont need it. I pull with Wormhole and if I'm not pulling, then Im in melee range.
Transport: Teleport friend for placing the Sing and team convenience, and then teleport for personal transport.
Speed: Hasten
Leadership: Tactics and Assault. (Again, with Drain Psyche and Power Sink, these two can just stay toggled on.)
Patron: Mu. Ill be taking the lot to give them a go before possibly respeccing out if I need. Power Sink is awesome, I can see the shield coming in very handy. The AE attack doesnt strike me on paper as too hot, but Ill see how it fits in, and Ive heard reasonably good things about the pet.
Ive gone massively off topic there, but thats what led me to the post in the first place.
So: Mental Blast. Now faster cast than subdue, the projectile travels faster than that of subdue, and it seems on par with other mid tier attacks from the other assault sets.
Stunning in a Omgwtfhax!!!11! way? No, not really.
Usable and worthy of a place in the set? Im beginning to think so.
Thanks for the replies guys - gave me something to think about. I'll give it some more testing before I commit to it.
[ QUOTE ]
... The attack chain is pretty tight, and the -regen stacking from dart and blast starts to become somewhat effective.
[/ QUOTE ]
-regen on mental blast and psi dart? Is this something new?
AFAIK only Drain Psyche does -regen...
Yea, sorry, -recharge, not -regen. Those pesky R words are so confusing.
hehe, long response...
Well, if u enjoy ur toon gettin a lot of powers because 'it may happen that in some conditions u would need those powers', then go for them.
I mostly play with 1 solid attack chain (it use to be single target), and try to avoid those 'situational' powers... But again it is ur toon, and u have to enjoy it.
Let me add that if u can get super speed, u could 'ghost' through a mob, and since sing is following u, it would take the alpha... I used to do that on Defuser and it really worked nicely.
And also, u can go to fighting pool, becoz the ppp shield + though gives u a roughly 60% resist to s/l dmg... That is pretty kwl.
Cheers.
There is no such thing as overkill in this game 
Looks like in your build, Mental Blast has a place, just doesnt really in mine at the moment, but its your toon, play it how you want.
Your comments about stamina were interesting, might look into that myself. DS + Powersink + Happy Button should be enough stam, but I think ile test it out on my domi first, as I run a few toggles, and Arctic Air now adds to my aoe damage (damage procs ftw!).
My Mind/Psi reached 28 recently, and so far has all (bar the final) primaries but only 3 secondaries: Dart, Blast and Scream. Mind/Psi is a fast set, and using Mesmerise, Domination and Levitate as required there is no downtime at all in the attack chain, Domination builds very fast and Mental Blast is a handy, reasonably quick, decent range, moderate attack. I agree that it's not going to rock anyone's world, but it's a decent power. With Mind/Psi you have nothing but time, anyway... 
U will gimp urself if u avoid mind probe, the biggest hitter in /psi until PSW...
Gimp? Hardly. Quite possibly I'll look at a respec in the future for MP, but for the time being I have no frequent need to close to melee range with so many rapid range attacks and Domination building so fast. The numbers do look nice though, and it's only now, at 28, that the secondary is making more room for itself, what with the primary being so darn good.
Once you get PSW and find yourself locking a mob down, then charging in, the playstyle of any /psi change dramaticaly. Its probably once you hit 38 that you will change your attack chain. Untill then, staying at range is never a bad idea. When you get PSW, it recharges so fast, especially wit set bonuses and Hasten up, that MP and subdue become about all you use along with it apart from your controlls.
no way! I think mental blast sucks so bad my normal attack chain is
PSW Mind probe PSW Mind Probe yeah that about it 
Got my patron started recently and was awarded the respec for it. Now, I'm not one of those guys who can sit on a respec indefinitely. It starts to burn a hole in the digital pocket after ... oh ... a day or so.
So, I copied Dreamseed over to the test server today to give the other travel powers, fighting pool and other powers which I just considered where garbage a decent go.
Mental Blast came as a surprise. Now I know they modified the animation so that the toon doesn't plant his feet at the end of it, and dare I say, it's not too shabby? Anyone else tried it?
That plus Subdue and Dart may just have a decent use now. The attack chain is pretty tight, and the -regen stacking from dart and blast starts to become somewhat effective.
I have PSW anyway, so the three shot chain would only be used for dropping the dregs that were left over.
So, anyone else tried it recently? Anyone actually have it in a current build and ... like it?
Honestly interested.