I personally think his 130 campaign is overrated. Yes he dominated everyone, but his opponents were far from great. Corrales was his best opponent there At 135 he looked vulnerable vs Castillo and Sosa. At 140 - not the best opponents, but Floyd looked at his best. At 147 - his current weightclass, some of his best wins here. At 154 - only 3 fights, but all against very good opponents. I'd pick Floyd at 140 as his peak despite level of opposition.
His tactics and skill were better at 147 than 130, as he gained experience from fighting so many great fighters and facing different styles. He was absolutely at his physical best at 130. He didn't have the speed, power, combos, offensive commitment above lightweight that he did at 130.
135 was Mayweather's best weight class and his natural weight class. His only notable wins at 130 are a shop worn Genaro Hernandez and a lead footed Diego Corrales. Hardly the stuff of legends. At 135 he did have the best win of his career. Looked pretty dominant in title fights. At 130 almost everybody he fought was just a complete and total bum. Flat out bum squad at 130.
He should of took a few more fights at 140. But he may have not got his dream the Oscar fight. Floyd got famous off Oscar. Anybody that denies this is a fuggin ignoramus! :verysad Then he spent the remainder of his career beating guys promoted and hyped up by Oscar as boogeymen that would beat Floyd. First it was Mosley, then Vicious Vic Ortiz, the young lion Canelo, they just kept coming! atsch These people have no morals.
He's differently great at each weight class. I'd say, however, that the version 130 is probably the GOAT at that weight class. He's arguably an ATG in 3 or 4 of the weight classes he fought at, which is something I'm not sure many other fighters can truly say throughout history.
Goyo Vargas and Jesus Chavez were former champions and better than Victoriano Sosa and Philip Ndou. Sosa and Ndoud had sparkly KO percentages before they fought Floyd but against sub-contender opposition. They were more one-dimensional than Corrales. And most thought he deserved to lose the first of his other two fights at 135, against Castillo. Anyway, the topic and the OP's suggestion that he was at his best at 140 where he fought even less than at 135, based especially on how he looked vs Gatti, implies that what's up for debate is more than just level of opposition. So you suck at reading.
At 147/54 Floyd's IQ was at its peak but his athleticism wasn't as visceral. 140 probably showed the best combination of the two.