I think you like fighters of a certain 'slickness'. There is absolutely no way that Ali, Mayweather or RJJ were more talented or skilled than Duran, Pep or Armstrong. And I cannot accept that Mayweather is on the same level as Whitaker or Leonard, not at all. Beating Chico and Judah does not make you one of the handful of the most skilled fighters ever. Truly great fighter, but not worthy of the very very top echelons.
This is, at most, a matter of opinion. IMO, all three are/were more talented. Duran was very skilled and talented, but his greatness also derived from factors other than talent (principally heart, balls and perseverance). In terms of alltime greatness, I rank both Ali and Robinson ahead of Duran. And I rank Leonard, Sweetpea, Jones and Mayweather behind him. Duran is my second favourite fighter after Ali, and I recognize his talent, and I don't much care for little Floyd, but to say "There is absolutely no way that Ali, Mayweather or RJJ were more talented or skilled than Duran..." is to express a purely subjective opinion. And in such matters, opinions are usually pretty fixed. There's much we see differently about the sport.