Healing should be a big decision making role. You should have to decide what to do, and when to do it. By seperating aoe into seperate spells you get more decisions, and it would be a lot easier to balance. Instead of having to balance every single spell in the game, all you have to worry about are the specific aoe spells.

I think a lot of legitimate arguments have been made but despite them, I do feel that seperating them would be beneficial. Especially since the combat system will be changing soon and will cause people to have to adapt to different things. If they make a change like this, that would be the best time to do it.