On the side note casters should NEVER hit ice due that damage reduction it has against spells, casters should focus on enemy melee that tries to brake ice instead or harass/cc enemy ranged/healers. Ideally you want only physical ranged and melee on ice duty while rest tries to stop enemy from hitting said ice, only time you want to hit ice as a caster is if its small one and you are alone in there other vise just focus players instead.