I've always wished my tank could hit multiple targets in ranged or melee (the mage overpowered thread made me think of this). So why not a catapult ranged weapon? Only 1 per team, damage depends on strength, etc, like other ranged weapons, only fires first round of ranged, and you buy boulders at the store?
So if those tanks keep complaining about only taking one target down at a time, they can use the catapult (which then gets abandoned as the targets close in for melee battle).