Junkrat and Mei are probably fine. I like the adjustment on activating Junkrat's ult. I think it could afford at least like 20 more health, or convert half it's health into armor. Mei players just need to stop blocking their own teams. I've had a Reinhardt's ult miss me because an enemy Mei froze herself between us.
Maybe Junkrat could get faster projectiles (with less gravity) but explode on fewer bounces, probably needs less damage too.
Hanzo and Widow could use better E abilities. As Hanzo's scatter shot is like, very, very extremely situational. He shouldn't be trying to damage things he can't finish off, and finishing someone off with it is very unlikely. Firing them in the open is practically useless other than looking at fancy lights. Widow's seems to just feed healer ults, especially Lucio's.
Torb's got a nice weapon, and the armor is a neat concept. But the scrap and turret aspects are what stop him from being consistently good. If his turret's ever killed, he loses out on a lot of potential damage and another set of laser guiding eyes, especially when it comes to ulting. And for someone with zero mobility and being perfect shotgun shaped, they seem to enjoy forcing him to run into enemy lines just to be able to have/give armor. In that sense, his turret is really only good for attacking payload, and defending point. And his armor is really only good for attacking at all, because when you're defending, you have to move away from the objective in order to increase your survivability. Overwatch is already doing a lot of momentum shifting, and having scrap/armor on top of that doesn't help too much. I think what would help Torb and Bastion to be honest is less firestrike damage.
As for Bastion. Deal a lot of damage but cannot even move. Sounds nice on paper, till you realize that Overwatch is a fast paced game with lots of mobility. Same applies to Torb's turret.
Once the enemy team knows where they are, they're as good as dead.
I think Bastion could sacrifice just a bit of sentry dps for a slightly faster deployment time and a bit more recon dps. Give his heal the shield he had before, rather than his sentry, but with reduced shield health (like, 150 or so).
And if the shield breaks, his heal goes on cooldown.