Im running 1 pally 1 priest and 3x mages and it seems to go ok for me.. im doing a few heroic bosses now and trying to get some gear for the pally. I have many times been thinking of switching to 1pally and 4xshamans mostly due to stupid fearing mobs. Its alittle harder to control 3 different characters too, but i guess you get used to it

Giz

1pally 1priest 3mages