3 spell balls only each
Those without a shield can roll a d6 at the start of the game and gain wild magic (Or opt out of using wild magic. Clerics/Mages/Elementals do not roll.):
Tracking/delaying the invaders.
Capture points and territory like risk.
Base attack with lots of fireball spells etc. Balistas (big slingshots) to knock down the gate to gain access (Both defender and attackers).