What fighters were better in their 2nd career? Foreman was better with technique and pacing himself, but still he lacked stamina and he still had slow hands.
Bobby Chacon and Bruce Curry immediately spring to mind. Neither had any realistic business winning championships over Bazooka Limon and Leroy Haley respectively, but undertaking fanatical late career training regimens carried each of them to those titles against the odds, after being written off.