I like a guy with a solid frame moving up in weight, if they had competitive speed and power, it should stay with him as long as he does not pack on excess, like Toney did, If James stayed about 210, he would have won his fights with Rahman and Peter ( I gave him the 1st Peter fight) and he is 39yrs old. Still I think when a fighter gets older he needs to carry more LBS and if he had power, he would keep it, Danger is excess weight that slows down a fighter and serves no purpase. Foreman fought at 217 but needed the extra weight and muscle to compensate what he had lost. In George lowest weight fight vs a 5"7 overweight Quawi, I think Big G. had a few scarry moments, thing with George was that he valued his stamina when he got older because it was something he lacked as a young Champ
I think Holyfield had more power as a HVY and I like Hayes chances if he has a decent chin. It all depends on how he puts on weight, he has speed and his power should get stronger but he can not compromise stamina
Definitely Ezzard Louis. When Louis retired Walcott and Charles were the two best men out there at heavyweight. Walcott was in his prime and a top 20 all time heavyweight.