Cotto isn't past his prime. Margarito is just all wrong for him. He broke him mentally and exposed him. Unless Margarito's chin has gone to ****, I think he wins or stops Cotto.
Hopefully cotto can get the win im thinking UD. Although pac has dealt both of them with pretty severe beatings and cotto has bounced back with a few decent fights. Where as this is margs first fight after a bad injury.
Steward himself said running isn't all Cotto's going to do. It's not black and white where Cotto either has to run and jab, or stand and trade. He can time his shots and follow up with combinations, and take advantage of his shorter punchers to get the better of Margarito on the inside before starting again. It's what Pacquiao did with his hand-speed and movement, it's what Mosley did with his reach, hand-speed, clinch and footwork, and it's something Cotto could replicate to some degree with his own abilities. Find the spots that enable you to dominate an offensive assault, and then box. His best bet is to mix it up. If he relys on running the whole time, he might get chased and broken down again. Miguel Cotto is better suited stylistically to fight as a smart boxer-puncher.
I'm a big fan of Cotto, but TBH, I don't see him winning a rematch. Sad but Margarito's style has always been bad for Cotto.