I'd suggest taking Hasten and Sonic Cage. Most people don't like cage powers that much but I find it to be a life saver sometimes. It requires some experience to know when and on which target to use it, but then it ends up being a very nice tool.
@False Fiction - Virtue / Defiant
Current projects - [Glaciologist - Ill/Cold Troller] [Cloudshaper - Storm/Dark Def] [Harald Wartooth - Elec/Psi Domi]
Is ths advise from the man who deleted his sonic? 
Harv, being team dependant you might want to pick something like hasten. Although not obvious with your build it's a power that will greatly help with all aspects of your controling primary powers and won't soak up loads of slots that I'm guessing you are fighting for at the moment.
I love the single holds on my trolleys, the quicker I have it to use again to stack on a boss the better - it generally gives an AoE focused team nice feelings to know that the boss ain't gonna be after them and their mass-aggroing ways.
Ive been playing my Ice / Sonic quite a lot (rolled primarily just to be different) and am mostly enjoying it. Ive been building it as team dependent, so its soloing speed pre-L32 is pedestrian to say the least (Ive just hit L28)
Ive been fiddling around with the powers and Im not really sure where to go next; Ive got the following: -
Ice: Block of Ice, Arctic Air, Shiver, Ice Slick, Glacier.
Sonic: The two team shields plus the big bubble, the L1 mandatory enemy res thing, the team-mate res toggle (yes I should know their names!).
From the pools, Ive picked up Hover-Flight, and Spring-Health-Stamina. Ive also grabbed Stealth with the purpose of making the enemies aggro on Jack when I get him rather than me.
Im likely to drop Arctic Air; whilst it does seem pretty good, I cant simply afford the two sonic toggles and it, plus be actively controlling.
So Im kind of at a loss of what to take at L30. If I respec out of Arctic Air I could jump into the medicine pool for Aid Other Aid Self. I could go with invisibility to give me stealth options for ghosting missions. I might go with Chilblain or Air Superiority to give me an attack option.
Any thoughts?