Its really hard to balance a perspective of what the "pros" already know to counter and overcome and the amateurs and below think its OP... Honestly i feel the game is pretty balanced and any major change can throw that away pretty easily... Like some ppl have said Widow can destroy a charge pretty hard, but the amount of ppl that have the capability to pull off that kind of target assessment/kill coordination is very small, even in what at this time we consider high lvl play iv seen maybe like 3 guys out of more than 6 or 7 teams have that kind of skill with her... But with time more ppl will showup with that kind of skill and honestly i myself im trying to get there, (play Sniper in every single shooter so) But you cant just nerf her cause she is actually balanced, like Zoidberg said for Mei its the same for Widow, she can be countered quite easily with chars that are actually meta right now even the terrain can be a counter for her, there are maps that after the first push she becames mostly useless...
Another major complaint i see alot is from Mei and Bastion, and this from a guy that spent every single min playing the beta and had quite a few hours in closed, i dont think they are OP because this is a matchup heavy game, if you play the MU you can counter them, BUT, and this is a big BUT if they where to be nerfed i personally would make the HP regen on her iceblock not regen as much, and i would put the Mag on Bastions alt mode at 150 and his reload speed increased just a tiny bit a few tiny frames... I read some talk about Phara being also pretty OP, i dont think she is, she is on par with other dmg dealers, things get a little crazy ( and this is map specific ) when a Mercy decides to dmg buff her on defense, then it can be REALLY hard to advance, But thats not on Phara lol thats on Mercy sooooo...
@Zoidberg747 Also from what iv been seeing Winston is an awsome "tankish" support for Reinhart push, he can go very quickly from def to batshit crazy on a def line... I personally dont fit his play style but i like to have one on Offense 90% of the time