So is it actually doable with 24 random people (no voice comm), lets say 66+ geared, assuming they know the mechanics and their role? If yes, then what should be the group setup? 2 tanks, 8-10 healers and rest DPS?
That highlighted bit up there is the important part. It was doable with a 24 man group in 61/63's before 2.0 if you assume everyone would know the mechanics and their roll. But, yes you are correct in the comp.