like our friend xeno says, if you die to an auto attack, find new healers. Meaning, if you get no heals and the healers ain't busy, just give them something to heal, aka turn the boss with a cleave right on top of them, have adds run after them etc. moment they lose 5 hp they gonna heal like a well oiled machine. Or kick them out right at the start. Can always train healers or extreme bad players.

Might sound horrible, but the last days have shown me, that if you don't go that drastic route, you're forced to not enjoy the game anymore, while "bads" that don't deserve it have a blast.