How is Cotto's resume deeper? He fought Pacquiao, but nobody else was that impressive, at least in comparison to Mayweather's comp. I'm not gonna pick through resumes, but Floyd has a long list of dominating wins against fighters who fit right in with the best opponents Cotto fought.
Floyd's awesome but he's had what, 9 fights in 8 years. He's also fought some limited opposition in that and doesn't take much punishment at the best of times. This is why he's aging so gracefully. As Mag said, if he was having Fab 4 type battles it would be a different story.
I'm not taking nothing away from his form. This form you mention emphasises my point. Wear and tear is very minor.
By fight time it was pick 'em. Hagler was about 6-5 fave early then it swung narrowly to Hearns and back to even by the time they entered the ring.