Even if I hate him ingame for me it’s gotta be Genji.
But that might also be because I love stealth games so I am really biased towards stealthy characters (ofcourse he isnt really stealthy ingame but he literally is a cyber-ninja).
A singleplayer game would also allow for a in depth talent tree since now they only gotta worry about one character + PVE balance can be a bit OP.
As far as I know singleplayer games aren’t really blizzards thing though which is kind of a shame. I think PVE in general would have been much better as its own game so you dont have to worry about balancing issues.
I mean reworking a hero when that hero also has a talent tree sounds like a nightmare to me.
Cheating and choosing two, but Sombra and Genji in a dual protagonist Watch Dogs style urban freeroam game with heavy emphasis on their movement and stealth would be incredible. Story could be about the two of them following the same lead without informing Talon/Overwatch respectively, one hunting the other down, or even the two reluctantly working together against a localized Null Sector threat (Sombra’s parents were killed in the Crisis, there’s no way she supports Ramattra even if Doomfist does)
Otherwise, Hanzo in a third person stealth optional takedown/action game (like Hitman x Sekiro) across future Asia explaining whatever he’s been up to and/or assisting in dealing with the Hashimoto and 2nd Crisis. His lore is so barren he’s basically a clean slate to do anything with and the idea of gameplay being dual wielding a sword and bow seems satisfying.