Well *I* want another resto shaman with a shield so I don't have to be stepped on all the time (heroic Morchok) and can dps every once in a while (heroic Ultraxion, heroic slime guy).
I think we have two tanks and two back up tanks, three healers and three back up healers (or 3 healers, a heal/dps hybrid and 2 backups?), and plenty of healers and tanks willing to dps. So I don't think role matters.
We have no warriors or rogues.
Yellow Moth loves warriors.