I never use Bully, and I always glasscannon the Fighter, they have the most health anyways so can afford to have less, and the best defense is to be aggressively offensive and your fighter is the big damage dealing killer, killing them faster makes your toons take less damage and ends the battle quicker.
Another thing to make your Tank really lethal is to give them scrolls, this makes the tank have a ranged attack that they expend o stat and skill points to use. The mage already has spells so should be usoing those not scrolls.
Teleport is a great spell it is the mages ways of saying "Excuse Me" your too close! and be sure and drop the teleportee on top of lava, in a fire or pool of water, in the tanks attack arc, or on top of another enemy, rain is really important as well. Aero and Ice attacks become much better when target is wet- so rain on their parade then chill em out or shock em up.
Heal is great, low colldown time and cheap AP cost with good range, and make sure you get every heal as it comes available having 3 levels of heal lets you heal multiple toons or the same one multiple times, keeps your tank in the center of the melee so they dont have to use Cure Wounds but can just keep swinging. Behind every great fighter should be a great mage.
