Plus if they had to go 15 rounds like the era Duran came up in... might be a totally diff story
Mayweather is amazing though, but styles make fights. Duran has the style that everyone thought Pacquiao would be able to bring last night. Maybe not as fast, but no way would he stand in front of Floyd clueless
However, when he fought Leonard the 2nd time and Leonard employed a semi Floyd-esque strategy, Duran got so sick of the running he literally said "no more" and just quit in the middle of the ring. He wanted to fight, Leonard wanted to dance.
So it really depends on what Duran showed up. If it's Duran at his mental and physical peak, I think he has a better chance to beat Floyd than anyone Floyd has ever faced.