Unpopular Opinion: Resurrect doesn't need a nerf/rework, we need a playstyle adjustment.

Don't get me wrong, some aspects of her kit can be too strong - 1-second until health regen could be too fast with how low the GA cooldown and how slim her hitbox is, for example.

Resurrect is fundamentally unfun to fight - it undoes that sick 5-man ult you just got - but we used to follow a saying: kill Mercy first or you'll have to kill her eleventh. People seem to have forgotten that. Mercy forces a different playstyle out of your team, encouraging hunting her down before using your ults. If she can get the res off that's a misplay by a Flanker player, or poor ult economy by the rest of your team. Keep in mind I Main a Flanker - I blame myself for letting that res get off.

She forces a different strategy the same way a Pharah, Builder, or entrenched Bastion does - you can't ignore them without paying the price. That's not OP, that's you being inflexible. It's unfun to fight a Resurrect all game, but no more or less than when the enemy plays "Protect the Bastion" or "Pocket the Pharah".