Its hard to say, I remember people thinking Mosley for going to destroy Mayweather and that didnt really end too well after the first couple rounds.
Can we really say Canelo is too big? Well, he was too big and Mayweather fought him and thats that lol
Mayweather is just a great defensive boxer. Dunno if GOAT but he is pretty good.
Who else did he beat? DeLeyoha (past his prime of course,) Cotto, Juan Manual Marquez, Judah, Gatti, a few other solid fighters.
I wish he had more under his belt and in different time periods thats for sure.
I like Manny P. more than Mayweather though. 1 of the few matches of what if it took place when it was supposed to take place.