Well I seldom use AoE on my teams, my locks and mage can do quite a bit of damage with AoE and ISBoxer which can make AoE very usable, in general I single target mobs and burn them down that way.
I agree with mail on a shaman it does make them more robust and the totems give a lot of passive dps,resists and heals.
With my arcane I just see a noticable dps lift, once arcane barrage procs he can be very deadly and it does seem at least once on each mob it procs and the mobs health bar drops like a stone lol.