Over a 100 games, I manage to maintain a decent 60% WLR with mostly just Mercy. Contrary to what people claim about not maining someone in a game like OW, Mercy fits into every team comp and map from what I have played. Also no one wants to play her so she's almost always available and even having another doesn't seem too bad even if the other Mercy goes Lucio when this happens often. When I decide to not play Mercy sometimes as games progress in favor of Symmetra or Bastion and no one else is playing her or Lucio, people seem to get mad or the games seem to get WORSE.