I don’t think McCree needs a nerf
Ashe is fine
Hanzo… TBD, I don’t think he’s actually as big an issue as Widowmaker. An extra second on Lunge cooldown would probably be okay, but I’d otherwise leave him alone.
Widowmaker… rework/nerf. I think one option is to drop her sniper damage from 120/3x crit to 100/2x crit. Then, buff Venom Mine to slow targets afflicted by it, slightly buff SMG (6.5/13 damage to 7/14 or so), and update Infrasight so that it also increases Widowmaker’s crit modifier by +1 (so 3.0x) and her team’s modifier by +0.25 (so 2.25x). That maintains her OHKO on squishies by reigns in the threat she poses to other characters, but also grants her greater value outside of her sniper rifle so that she’s not as big a joke if you can’t dink heads. Just one example, I can think of multiple other options that I would personally find acceptable for Widowmaker