Mayweather already beat him once. There is nothing else for him to prove. I wouldn't support it or buy the fight.
Ali was superior to Marciano in all aspects except power, marciano was not even a true heavyweight (he was a cruiserweight but this division did...
I think Khan will win.
Floyd Mayweather's technical capabilities would be to much for Bradley. Mayweather would win by decision.
I think Wlad will win the rematch. I think his determination to avenge his loss will be to much for Fury.