Mayweather isn't a big welter
I'll keep it short because there isn't really much discussion.
Why do a lot of you think that Mayweather should fight guys like Martinez, Canelo and Trout who come in at 165-170 on fight-night? Trout pushed Cotto around like he was made of paper.
Even your (our) late hero Emanuel Steward said that Floyd was a small welterweight. He said it on two occasions - once against Hatton and once against Mosley.
The first apparent indication is that Floyd comes in at 151, at max - and that's for a middleweight fight.
What makes you think that Floyd belongs in the middleweight division?