My Mage/Mage/Pally trio is amazing. Group heals are NOT necessary as you have amazing agro building with the pally for groups. Healing isn't an issue either as you have enough talents designed to push through the interupts that you can channel through the damage.

Two shields for emergencies, and rez if shit gets REALLY ugly. Running is always easy if you are in over your head, round robin the frost novas and you are sure to stick everything that can be stuck to the ground.