[PantherPrincess]

I'm more so referring to Hi-Pots which are accessible on Korvara, which is 200 HP back, and then there's also bandages which can be used outside of battle. A specced out Graft user hits around let's say around 200 or 214 HP let's just say for a guesstimate. While they're not AoE (aside from bandages) they're free of charge in terms of FP which is their pro. As for the argument at hand, I am simply pointing out that all of the points OP made are seemingly based on his pvp experiences (which there is nothing wrong with it just ties into my comment about build scenarios and team compositions) currently and I quote: 

"So here's a simple suggestion, since AOE healing is known to be an utter pain in the ass for teamfights, mostly due to negating entire turns of attacking and actions for no more than 3 momentum, often blocking a team with most of it's firepowering options shut down into an eternal struggle.

So here's a rather simple suggestion-

For each player ally healed, healing gets -15% efficient, capping at around 60% total efficiency. Healing would definitely remain extremely strong that way, but it actually would mean a side that does not have it's own AOE heals/ ways to disable opposite healing would stand a chance in a teamfight."

While a whole team of healers can certainly be oppressive in certain scenarios, I don't think being unprepared for a healer warrants for a nerf. Team compositions sounds more of an unlucky draw than a balance fu thread. There are many forms of interference in the game ranging from magic gunner to evoker to LB itself and even black knight. I just don't see how much more you can remove from them while still retaining cooldowns that already hinder them from spamming it every round and retaining any sense of use before the damage negates the heal itself completely. Because you can already do that depending on the scenario. Keep in mind action economy plays a huge role in a healer too. Not just FP, cooldowns, silence, interference.