People forget they guy who threw a zillion punches a round and remember the guy breaking his fall with his face against sexy Sergio.
After Williams beat Margarito in 2007 I swore up and down that he'd beat Floyd, and then the first Quintana fight happened... and obviously since then Martinez gave him fits with his movement and then Lara looked like a million bucks by sticking and moving. So, no, now I don't think that Williams would have beaten Floyd.
Mayweather would of completely dominated Margarito. It wouldn't of been close.
How does Maro hit Floyd? He's simply no where near fast enough to connect in the center of the ring and if Floyd did let him tee off on the ropes, he'd be hitting hips and arms whilst getting countered.
Floyd isn't Miguel Cotto, he knows how to fight on the inside, he knows how to hold and turn off the ropes and most of all he's much more athletically gifted. He could pot shot Margarito for 12 rounds and not lose a breath.
Let's face it, the only reasons Margarito had success against Cotto was because he got tired, when he wasn't tired, he was dominated. Mayweather doesn't get tired. He'd tax that arse for 12 rounds straight.
Mismatch.
Almost agreed with everything you just said but, let's face it, Margo success against Cotto was because he walked through Cotto's punches and landed a lot of powerful punches to Cotto's body. That's why he got tired and slow down. Margo's uppercuts to the body were ones of the most devastating I ever seen. Also Cotto stay in the pocket to much instead of stick n move pretty much like he did in the second fight. But still he was just surviving and it was just matter of time to get beat up at late rounds. But the stoppage came. The strategy of hitting that eye really works.