If Sugar Ray Leonard and Tommy Hearns fought each other with a 12 round fight would Tommy Hearns have won that first fight? Sugar Ray Leonard vs Hagler; If the fight went 15 rounds would we be viewing Sugar Ray's legacy differently? Would DLH have lost to Tito convincingly in a 15 rounder? Just thinking about the difference in fight outcomes then and now. My answer to all of these questions would be yes.
I'm not sure what would happen since fighters would react differently knowing there were more or less rounds. I do think that DLH would have quite a bit of trouble in the 15 round era. In the fights in which he's fatigued and lost, I think he trained really hard and was in good shape, but was too tense during the fight and that can take a toll on a fighter's stamina.
Right. Pacing, strategy, training: everything would be different. It's not just three rounds tacked onto the end of a twelve-rounder.