Well, I mean, for me, it tends to be tank runs in hits them once, I start casting Blizzard 3, 3 seconds later, the tank has or should have flashed/hit all the mobs/whatever so I cast my AOE sleep. Then noone has to worry about any of the other mobs because they aren't doing anything.

But then, I always get amused when a healer thinks it is a cool idea to break all my sleep targets so he can put some weak dot on them... like he is somehow "helping"... when he would be able to better contribute by just sticking to single target since it means less healing he has to do on the tank, so more time spent doing DPS.

I very rarely run with BRD and SMN as the other DPS, so ideally the mobs should be slept when possible since it makes the run so much faster. If If get a BRD or SMN, then I would prolly just AOE spam them down myself.