Good question with a lot of possible answers. There is a small list of fighters that Mayweather missed but the more his career progresses, the less relevant they seem to be. Pacquiao is the only one who really warrants discussion. You could argue that he missed Antonio Margarito or Paul Williams but if you make a list of fighters Floyd missed, they all become less relevant because they lost, either to lesser opponents or in ways that were so violent that any mention of facing Mayweather became moot.
Then you have Cotto and Mosley but those fights didn't give much in the way of hints of how they would have been different any other time. Sure, Floyd could have fought each at earlier times but I don't think it would have been different. There was never a doubt in my mind that he would have embarrassed Cotto at any time. Cotto is just too slow.
Some would argue that Mayweather is avoiding Canelo Alverez but, if Floyd never faces Alverez, I don't think it does anything to his career. Alverez wasn't bellowing so loud a year ago. Now that Floyd is 26 --to Canelo's 22-- the chirping gets louder.
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Ray Leonard doesn't have such a list. There are two fighters that come to mind but there isn't a strong enough argument for either. Much is said of Leonard's "missed" opportunity to face Aaron Pryor. However, with timing, Thomas Hearns was the more lucrative opponent. Leonard could have faced Pryor a bit earlier but it could be argued that only die-hards knew who Pryor was.
With plans to face Hearns in 81, after regaining the title from Duran, the second title against Ayub Kalue was more attractive than a defense against Pryor. Leonard fought Larry Bonds after Hearns and there was again talk of facing Pryor. However, those plans were derailed by Ray's detached retina.
Mike Tyson's list of missed opponents is far greater than that of Leonard's or Mayweather's. Pick your reason but most of it was politics. There are two exceptions. Lennox Lewis and George Foreman. Team Tyson avoided Foreman in every possible way. There was just not much belief that Tyson would win. They also avoided Lennox Lewis, a foolish move. Had Tyson faced Lennox earlier, he might have had a better chance of winning. By the time he actually did face Lennox, he desperately needed the money and he was no where near able. He had a puncher's chance and even that was slim.
Muhammad ALI has no such list. There is not one fighter, during either of his reigns, that ALI missed. He fought Everyone.
Larry Holmes missed Greg Page but, again, that was more politics than any fear. I don't think Larry knew the meaning of the word fear.
Duran missed Arguello.........Or I should say Arguello missed Duran. Duran wanted the fight but when it didn't happen, he went after bigger fish, in the name of Leonard.
Joe Frazier missed Sonny Liston and Ernie Shavers. That's right. Yank Durham avoided the aging Liston until Sonny's death in Dec. 1970.
Vitali and Wladimir have cleaned out their division, missing no one.
You could argue that Oscar de la Hoya missed Winky Wright and Vernon Forrest. However, there were always more attractive opponents for de la Hoya to face. He faced most and there is little room for argument for those he missed.
(Not ordered)
1. Mayweather Vs Antonio Margarito
2. Mayweather Vs. Kosta Tszyu
3. Juan Manuel Marquez Vs. Eric Morales
4. Chris John Vs. Pretty much anybody
5. Sugar Ray Leonard Vs. Aaron Pryor
6. Roberto Duran Vs. Alexis Arguello
7. Felix Trinidad Vs. Ike Quartey
8. Joe Calzaghe Vs. Sven Ottke
9. Mike Tyson Vs. Either Klitchko
10. The ones you mentioned.
Foreman-Holmes
Frazier-Norton
Bowe-Lewis
Espinosa-Hamed
Tyson-Bowe
Naseem Hamed vs Juan Manuel Marquez
Naseem Hamed vs Erik Morales
Calzaghe vs Froch
Gatti vs. Hatton
I would really love to see a prime Mike Tyson vs prime Muhammad Ali.
none of those compare to this fight:
only true boxing fans would know that the greatest boxing fight would have been Teofilo Stevenson vs muhammed ali
tyson at his prime was class
he was in a crap division with nobodies
its a shame he was not around with ali, foreman , frasier, norton
tyson was great his opponents were not
Examples: Mayweather/ Pacquiao, Leonard/ Pryor, Prime Tyson/ Lewis
