Threeboxing with a healer (Pally) and two mages I went a different route, I focus'd on the Arcane Tree for the mages and holy tree for the paladin. Pallies have great AE threat generation ability and I can generally pull 8 mobs and keep them on the pally for the majority of the pull. Arcane Explode them, maybe throw some cones of cold in (still getting the hang of that, it's often I blow snowcones out into the wings and not hit any mobs )

I went with arcane spec because of the resists, it allows me to grind on higher level mobs and with a mail tank (soon to be plate) it grinds so nicely.