Who was actually better?
Just watched documentary on Duran on how he was out of shape and they didn't give him the time he wanted for the fight
Duran had a habit of being undisciplined, partied, drank, whatever you want, for him it was a pain to make weight even for a guy that was small-framed as a 147er.
Leonard later said they knew about this habit and they pushed for the immediate rematch immediately, with that said can't blame Leonard for exploiting his opponent's weakness like that, first and foremost it's on Duran to stay disciplined.
Good question who'd have won if the Leonard from the rematch faces the Duran of the first fight but I tend to think even with a better Duran Leonard found out what to do to beat him and would have executed it either way, maybe in a tougher fight (iirc the no mas fight was pretty close as well until a round or two before the "no mas").
So if they'd fought 10 times I think Leonard would have won more of them.
Historically Duran is greater though cause he started out from 135 and became arguably the greatest 135er ever, but at least a top 3, for him everything above that was extra and he got some nice wins under his belt in higher divisions even with the occasional upset losses.