Uhhhh… Come again? In what universe do you currently reside in, OP? Moira most certainly isn’t nerfed, just because Mercy was, lol. Moira is very viable right now. Hell, even Mercy is still viable (Mercy/Zen is a strong comp at the moment).
A. Zen has always been a solid pick, even since day 1, so nobody will complain about one on their team.
B. Lucio had a pretty high pick rate for a while, much like Zen, before Mercy got buffed (Lucio/Zen used to be a pretty common comp back in the day). Even now though, Lucio is still pretty good for his defensive ult if you’re running Mercy or Moira as your main healer.
C. Mercy may not be as good as she was before, but that doesn’t mean she’s bad now. You still see her regularly in competitive play and in professional play as well.
D. Moira has been a solid choice as a primary or secondary healer since release, so she’s not going anywhere any time soon.
E. Ana is the only healer who is in a rough spot right now because of how popular barriers are in our current meta. It’s incredibly difficult for Ana to heal because of barriers and a Winston is usually jumping on her in the back line to shut her down, so it’s just safer to play someone like Moira since her orb can go through barriers (but I hear this is a bug and will be fixed at some point).
In any case, Brigitte definitely brings more to the table, but as a secondary healer, so she’s definitely not going to be taking the place of Mercy or Moira, that much is certain. Between applying armor, healing, and having a defensive ult though, she will more or less just be another Zen or Lucio in terms of picks, so we’ll probably see her in a lot of matches since Rally can not only help defend your team against a push, but it can also help you initiate a push and get through a choke (much like Transcendence and Sound Barrier).
Anyway, it’s probably best if you stay away from the game though since you’ve already made up your mind about how the balance is, OP, despite what’s actually happening to the game.