Widow's wallhack should go away when she dies. she shouldn't really have an SMG i don't think, if you risk trying to go through the entire team to get to widow you shouldn't be penalized by having to face a DOT trap and a powerful SMG...
mccree flashbang should have a bit more range and just blind you for one or two seconds but still allow you to move. junkrat's trap makes sense for movement restriction but flashbang doesn't.
roadhog's hook should be less forgiving in general and maybe allow him to launch himself? that would be hilarious
76's ult is stupid and should just allow you to have no recoil and maybe crit damage or no reloading during the ult.
maybe lower damage on symmetra/winston unless you are tracking the person and have a quick ramp up rewarding good aim
genji should have some arc to his shurikens, makes no sense that he can throw them perfectly straight forever but hanzo's bow has an arc. genji reflect should also have some sort of skill involved like airblast in tf2. hard though with client-side reg. i also don't see the need for him to have wall climb...double jump and dash is enough
tracer needs some sort of hard counter from medium range. or maybe just reduce her medium range damage slightly.