Corbett and Braddock jump out at me. If adding the major Alphabet groups, Ellis would be a fit here, and Byrd.
Vitali's power wasn't great, but it's definitely not down there with some of weakest ever. Corbett and Sharkey take the cake for lineal champions IMO. Fury might be the softest punching 6'9 fella ever. Edit: fixed a pretty crucial typo.
I'd replace Ellis with Ernie Terrell. Ellis could really pop with that right hand. One of the few men who could say they dropped Oscar Bonavena. And he did it twice.
The only way Braddock hit harder than Vitali is if he was swinging a bat. Vitali could absolutely crack and should not he mentioned at all.
True but if you have no power you can hit an opponent all day and they won't be stopped unless packing glass, Vitali could hit, not a concussive puncher but his record suggests he had more than enough power.
Sorry mate, I've realised what I wrote before. I agree he's no featherfist, I just don't think he's close to a great puncher.