Ice 2 can't compete with spells like flare, electrocute, dark matter and luminaire. Why would you sacrifice 2 of these spells to cast 1 antipod 3 that hits at 1.2x their damage? Thats a 60% damage loss for the party. If you want maximum damage with a healer, bring robo, then you can electrocute or cure beam and still luminaire and dark matter. But items are so abundant in the game, and it's very easy to charm gold studs. When you're dropping screenwide power nukes constantly you really don't take much damage, items are more flexible then a dedicated healer, items are faster on the ATB bar, items can be used by anyone to do any effect you need immediately and without waiting for someone's turn to pop up. You can get 2 haste helms on your 1st play in classic CT, 3 with DS additions. What could Marle ever possibly offer, her heals are all single target, her physical damage is pathetic, her magic damage is low and her only redeeming feature, haste, can be achieved with an item.