While I appreciate the attention this has gotten, the topic has, sadly, deviated from discussion around actual bugs to one of perceived balance. If a mod happens upon this topic, it would be fantastic if everything after the bug reporting was split off into a different thread and tossed into General Discussion.
Yes, the inability for teammates to target her is a nerf, but it’s not insurmountable. Temper your aggression and relegate cryo to blocking abilities and LoS. Treat it like an instant half-pillar ice wall rather than a sustain.
As far as Moira’s healing is concerned, her ability to target Mei has been a turbulent one, but the intent and functionality before this nerf was such that she could heal Mei in cryo. Granted, it’s a moot point now as no one can, but that’s how it goes.
Mei has 120 ammo, and even with the extra tick required to freeze a target, that’s enough for two unoptimized freeze cycles per clip. If they fix the extra tick bug, that goes back up to three (more than enough to kill the majority of the roster unassisted). And the double- and triple-tap techs are still alive and well.
Lastly, winrates and pickrates are not indicative of balance, nor perceived balance – especially in an environment where the bulk of players are deriving their playstyle and strategy from common sources (i.e. streamers and youtubers). You can still have success with Mei at all levels of the game, even in the buggy state she’s in today.