@Gorani: water magic has quite a bit of damaging spells, so you still play offensively. Even though it's weak against foes it still counts as doing damage. Also, you do damage indirectly by keeping others alive longer, which allows them to play more offensively.
@Bearsfwd: if you mean playing support-only, then I don't know. For the record though, it's easier to play hybrid than support-only, you'd be wasting time if you didn't throw in a few damage spells between heals.