Healers are supposed to heal and provide support, not squeeze as many Glares or Broils as possible in their actions.
-Reduce team mits, especially tanks, yeah
-Remove healer attacks completely. If you want damage, give them more abilities that buff other people
-Bosses will now do random, unpredictable attacks of different types against random players, that require the healers to react. Not reacting fast enough=punishment
But as someone said, these won't be happening unless they do some revolutionary changes about the encounters first.