Following his fight-of-the-year caliber performance against Cotto to earn the WBA alphabet title, Antonio Margarito has established himself as the de facto king of the division. Cotto didn't end up too bad, either, and should be in line for another alphabet title shot pretty soon. Margarito has already called out Oscar De La Hoya (whom he would easily destroy) and has said he would be willing to face Clottey again (whose chin is just as strong and could make it interesting). But the fight that everyone wants to see now is Margarito and recently retired Floyd Mayweather, Jr.
Mayweather recently stated that he feels his legacy is secure, and that he has nothing left to prove. That is true in the lighter divisions where he vanquished Jose Luis Castillo, Diego Corrales, Angel Manfredy, Emanual Augustua and Genaro Hernandez. But at 140, he dominated Arturo Gatti and DeMarcus Corley while ducking Cotto, Kostya Tsyzu, Ricky Hatton (whom he beat in 2007), Junior Witter and Vivian Harris. At welterweight it is even less secure, with only Carlos Baldomir, Judah, De La Hoya, Hatton and Sharmba Mitchell on his resume there. While these guys were champions, they were either on the downside of Hall of Fame careers (De La Hoya, Mitchell), too small (Hatton, who had no business moving up and still made a fight of it) or simply had a title (Baldomir).
Mayweather has not taken a serious risk since moving up to 147. Hatton arguably hit him more than anyone ever has in their fight, and Hatton is much smaller than the men Mayweather will need to beat if he is to truly cement his legacy as one of the greatest fighters ever and not as an overpaid, overrated mercenary. That's where Margarito comes in.
Margarito would destroy Mayweather if they fought. Floyd does not have the power to stop Margarito or even slow him down. If the "Tijuana Tornado" could walk through Cotto's best shots, he would laugh out loud at Floyd's as they were coming. Floyd also had to be wondering if he could have taken the shots that Cotto landed on Margarito in their fight, making Cotto also more likely to beat Mayweather head to head.
Of all the top welterweights in the division right now, Mayweather probably beats only Judah (which he already has), Andre Berto, Carlos Quintana, Luis Collazo, and maybe Kermit Cintron. I wouldn't even give him the nod against Clottey, whose superior strength and technical prowess would carry the day. Floyd's also run from Shane Mosley numerous times, and let's not even talk about what Paul Williams would do to him.
Floyd, you're very gifted, but you're a coward, just like Roy Jones used to be. You want to put on a display of athleticism against guys who aren't even in your class to make yourself look better. If Sugar Ray Robinson and Henry Armstrong knew what you were doing, both of them would rise from their graves and take turns beating you senseless.