I think that almost everything would have been fixed if healers weren’t so oppressive when stacked.
First of all there must be a limit on healing rate, so it’s impossible to heal 300hp in a second. It’s stupid, because headshot that deals 300 damage is so much harder to apply to a hero.
Then you add diminishing returns on heal stacking, same as in Team Fortress 2 where for every healing source that affects target, there is a penalty to healing. Two medics healing same target at once, only heal at x1.5 rate not at x2.0 rate or something.
Changes like this would actually make heroes with less than stellar damage output playable again, because nowadays they can’t kill anything. Focusing heals is much easier and more effective than focusing damage. This should not be the case.