About healers just standing around in leveling roulette, for myself especially in the start part of the run I give it a bit to see how the rest of the group balances out. And some places while things are seeming to go well can be just hazards waiting to happen where I might need to go healing spree on moments notice. If the group seems to handle stuff, I shift more and more to the dmg side but only when I know it's safe to do.