I know that people don’t want to hear this, but…
It’s rez on cooldown that makes Mercy a must pick. That kind of utility in a healer’s base kit is too good to pass up.
Valkyrie takes it over the top by eliminating all of Mercy’s weaknesses. Anything that would have previously pressured Mercy to switch can now be ignored by flying into the skybox with permaregen, while the AoE chain beams do the rest.
The rest of Mercy’s kit (basic beams and GA) wasn’t a problem pre-rework. It’s the fundamental design of Mercy 2.0 - having rez as a basic ability and Valkyrie as an ult - that has broken her.
Neither nerfs nor buffs will fix this. Mercy needs to be reworked again, this time without an ult on cooldown or an ez mode Q.