Well healers aren't as critical... though... the healing part of keeping a tank alive during multiple mob spam... I would like to hear from healer players on that one. Because that's a lot of Damage incoming on the tank. I've done it with SCH so I know very well you have to be on the Ball.

I do know WHMs will usually spam Holy during AoE encounters and SCH will alternate between heals and Art of War spam. Healers its more about making sure that Tank who has enormous amounts of mobs on him stays alive long enough for people TO burn them down.