why do you link the effectiveness of Aim and Build-up to having a snipe attack??
if anything, I find that Aim and Build-up are even more helpful to a fast cycling stream of attacks, like Ice. you can easily get off 4 or 5 attacks within the 10 second window of these 2 powers and get around 40 - 100% damage/accuracy bonus.
after ED, that extra damage bonus is very, very nice on all attacks, not just snipe. in fact, I find it less useful on Snipe now, because with ED, you can't slot enough damage enhancers in Snipe to be able to take our higher lvl LTs like you used to with BU + Snipe.
if you are concerned with having to get closer to Mobs before activating Aim or BU, then get stealth as one of your power pool choices. let's you position yourself right where you want to be. hit aim/BU, then unlease Icy Death 
I completely agree. I constantly cycle Aim and Build Up so much I had to three slot them with Recharge Reduction Enhancements. I really can't imagine getting by without them.
There are several ways to play an Ice/Ice blaster in City of Heroes. The way that I play it is pretty much 3/4 Blaster, 1/4 Controller. This allows for a lot of versitility based on the situation that you find yourself in. Another common way to play an Ice/Ice blaster is Blast only, which causes massive amounts of damage, but is a lot more risky for a solo player. The third common way is the Blapper type, which bases a lot of its damage on melee range and short range attacks. Ice is not the most effective powerset for this style of play, so my information on this method will be fairly minimal.
Primary Powers:
The three main primary powers are fairly similar single target range attacks. All of these three powers should be taken, allowing for a three attack run which will quickly take down almost any even or +1 minion, and will take down many +2 minions. Two runs through the three powers will take down most even con Lts and some +1 Lts. They are;
Ice Bolt
Ice Blast
Bitter Ice Blast
The order that I usually take these powers is Ice blast, Ice bolt, Bitter Ice blast, and I take them as soon as possible.
Ice bolt and Ice blast are both fairly long range attacks, and Bitter Ice blast is a medium range attack. Since ED hit, I avoid stamina and hasten, and instead slot these three powers as follows; three Damage, one Recharge, one Accuracy, and one Endurance Reduction. With these powers slotted this way it is possible to do massive amounts of damage with very little endurance and a recharge time that is a little longer than pre-ED perma-hasten.
The third attack in the set is Frost Breath, a medium range AOE cone attack which does about the same damage per target as Ice bolt. It also causes a good amount of slow, and until Shiver is available from the secondary, it is usually wise to slot it for slow.
Aim is the fifth power in the set, like most blaster primaries. Many people swear by this power, I tend to avoid it. What Aim does is it is a short term to-hit and damage buff. Since Ice really has no snipe, this power has limited utility.
After Aim is Freeze Ray, a mid to long range hold. This power is extremely useful to a solo blaster, and is fairly useful to any blaster. I usually don't slot this attack heavily and tend to concentrate on accuracy, as it gets used in tight situations very frequently. This attack can hold any minion or lt that it can hit, duration is shorter when the enemy is higher level than the attacker.
Ice Storm is the seventh power in the set, it is a ranged AOE attack, and it does minor DoT. The damage on this attack increases based on how many enemies are in it's radius, and how long they stay there. When used with Ice Patch from the Ice secondary, it can be a very effective tool to thin out larger groups.
The eighth power in the set is bitter freeze ray, a single target hold, much like freeze ray, but it takes time to activate, and deals quite a bit more damage. The best use for this power is as an opening attack against a boss, followed quickly by Freeze Ray, effectively holding the boss for a short period of time. Accuracy enhancements in this power are a must, allowing you to hit with little error.
Blizzard is the final attack, similar to ice storm, only a lot more powerful, and with a knockdown effect added to it. This basically works like a large Ice Patch and a heavy damage version of Ice Storm, all rolled into one. Because of its end drain which takes your endurance to zero and prevents you from regenerating end for the duration of the power, it is wise to use this as either a emergency escape power, or carry endurance inspirations to allow you to attack the slowed and knocked down opponents. I like to use this in conjunction with shiver and Ice Storm, stacking the damage and slow from those two powers on top of its effects.
Secondary Powers:
The Ice Manipulation secondary has a few really nice powers, some powers that are OK, and one that I would suggest skipping, if it were possible.
Chilblain is arguably the most useless power in this set, but you can't skip it. What it does is immobilizes a single target and deals some moderate damage. I usually slot this for either damage or accuracy, using the default slot, and it is almost always removed from my power tray by the time I reach level 10.
Frozen fists is the second power available in this set, and is a rather nice melee attack, it slows the target as well as dealing minor damage. I don't usually take this power, as I prefer the higher damaging Ice sword.
After Frozen Fists comes Ice Sword, I would suggest getting this power if you need any melee damage other than brawl, and you don't want to take the attacks from your pools. The attack deals moderate damage, and has a chance to slow.
Chilling embrace is a nice power to pick up after you get your travel power, it slows all nearby enemies, and is auto-hit. The reason that I like this power is because it has a chance to de-cloak Stalkers in PvP
The fifth power in the set is Build Up. It is similar to Aim in almost every way, but it buffs damage more than accuracy, where Aim buffs accuracy over damage. This is another power that I don't normally pick up, due to the fact that there is no real snipe in the Ice Blast powerset.
Ice patch is a must have power for almost any Ice/Ice blaster, it creates a small patch of ice that knocks down enemies and significantly slows their attack rate and movement. The best way to use this power is by laying the patch in a doorway or hallway that is no wider than its radius, then attacking and pulling enemies through the patch by ducking around a corner on the other side of the patch.
Shiver is the second must have power in the set in my opinion. Shiver is a medium range, cone AOE slow, significantly reducing the movement speed and attack rate of all enemies that it hits.
The eighth power in the set is freezing touch, a melee range hold. I really don't suggest getting this power unless you plan on becoming a half-troller instead of the quarter-troller that I usually play.
Finally comes Frozen Aura, a PBAOE sleep which affects a radius based on the location of your hero. This power has limited real utility, and should be used as an escape power, as any attacks break the sleep that you initiated.
Build:
Since this guide is about the Ice primary and secondary for blasters, I will stick mainly to talking about how to pick and slot those powers, based on my two ice/ice blasters that I have leveled to 40. I will not go into the Ice Mastery powerset, as I have very limited experience with it at this point in time.
1: When you create the character, you are forced to take Chilblain (you already know my irritation with this power, so I won't go into this any further), and are given the choice between Ice Bolts and Ice Blast. I always choose Ice Blast for the higher damage early on.
2, 4: The next two powers that I get are Ice bolts and Frost Breath. Slot these first three attacks early. With ED in place, slotting more than three of one kind of single origin enhancement is pointless, so when I initially slot these powers, I slot them the same way I will have them slotted with SOs. Three damage enhancements will yield the best results, followed by one or two accuracy and a recharge reduction enhancement. If you choose to slot one accuracy, a good idea is to slot endurance reduction, especially if you don't plan on taking stamina later on.
6: Next I choose the first power in my travel pool, this is a personal choice, but I tend to pick either jump kick or air superiority, negating the need for a melee attack from my secondary, and taking out the need for a power with a negligible defense buff.
8: I like to pick teleport friend or chilling embrace at this point, depending on how often I think I will have a SideKick.
10: Freeze ray is next. I usually give this power three or four slots over the course of my character's life, concentrating on accuracy for two of them, and the remaining slot or two get hold duration.
12: Ice storm is next, and it should be slotted heavily for damage and accuracy, three of each. This means that you will hit more often for more damage. Slow is also a good use for one of the slots in this power, replacing one of the damage enhancements.
14: After Ice Storm, you should be level 14. It's in your best interests to get you travel power at this point, making it much easier for you to get around.
16: For your next power, it's really a matter of preference, once again, either choosing chilling embrace (if you didn't already get it), Aim, Build Up, or a pool power. Since I usually get Teleport friend at level 8, I like to pick up Chilling Embrace.
18: Finally Bitter Ice Blast is available, rounding out your three attack combo. This power should be slotted as soon as possible, in the same method as Ice Bolts and Ice Blast.
20: Ah, capes... and just as importantly, Ice Patch is now available. I don't normally add any slots to this power, and fill the one slot it comes with with slow.
22, 24: This is a chance to diversify your power pools, either that or pick up Aim and Build Up if you haven't yet.
26: Bitter Freeze Ray is now available to you, giving you the power to hold bosses for a short time when used in conjuntion with Freeze Ray. This power should be slotted the same way as Freeze Ray.
28: It just gets better and better, doesn't it? Now you should pick up Shiver, slot this power with slow, cone range, and accuracy to taste. Two accuracy enhancements are really nice in this power, meaning that you will almost always hit all enemies in it's cone.
30: Another chance for you to diversify your power pools, picking up anything that you think might come in handy later on down the road.
32: Your final power from the Ice Blast primary is now available, Blizzard. This power should be slotted with accuracy and damage almost exclusively. Endurance reduction is fairly pointless, as the power takes all of your end anyways. Slow is of little use, because the knockdown effect makes the enemies seem like they are much slower than they are.
35: This is your final chance to finish up your pools before all of your primary and secondary powers are available.
38: Your last Ice power is now available (provided that you don't choose to continue with the theme and get Cold Mastery), Frozen Aura. I have limited experience with this power, so I will refrain from commenting on how to slot it.