Wasting an effect would be the same thing as mis-clicking a target to who you want to combo or interrupt. Target selecting? Its a full team heal as if putting it on ones self, same as applying scarlet's shield to another team.
I get what you're saying but I don't see that affecting anything? If you yourself are healing another team and choose to waste your heal that is your own decision in doing that, not anything with the game. That would've been an incorrect calculation in the fight and a nick in ones own strategy and that fault is on the caster. And ofc you'd want to keep your team healed up, for instance I'd run azure fang, sailor sakura, Hanzo/Tsunade, Jigokudo. Off my standards I'd be healing nicely and still be able to apply heals to other ninjas. Now Either I get focused out or you hit the damage dealers, that's on the opposing team to choose to do so. This is in no makeshift a damage team pure support.
My idea is for a more fault support ninja team instead of an blitz or bruiser team. To add something to GNW and the 12v12 ninja fights.