"A good big 'un, beats a good little 'un?"

near enough accurate, but most Catchweight contests were always met at agreed weights Not Exceeding X amount of pounds, the larger man having to shed a few lbs or more, with the lighter fighter coming in more or less what he wants, being 'lighter' to begin with.

In many a case, it wasn't just a few pounds heavier either for the lighter man, but anywhere in the range of a couple of lbs to as high as even 10 lbs heavier than his divisional weight for the 'lighter' fighter.

also as to the generalization of the bigger man and 'Weight', I have highlighted in your post, I agree basically too with what you have said, but too many people get lost on the Weights of the bigger fighter, especially if it's not too great of a difference, But this is Still the Wrong way to look at it...

the Bigger Man is solely - the Disparity - of HEIGHT & REACH that Can't be overcome for the 'smaller' fighter, the weight is the 3rd factor and no where near the problem of the first two hurdles of Height & Reach.

 

Pacquiao moved through the weight classes really well, and at WW he was always the smaller man. Hell against Margarito at Super Welter he was only 144 or something.

 

This to me is a complicated question. You have guys who don't seem physically extraordinary that can climb weight classes like a ladder, Langford, Walker the most famous two i can think of, could compete at the championship level in nearly any class. I think at the end of the day, if boxing was freeweight and a guy like Robinson can show up at 175, and his opponent is 212 pounds (and if the ring lights and temperature didn't cause heatstroke unlike his fight with Maxim) that he can be game enough to win somehow

 

Pac beating DLH

 

I think any decent, world level heavyweight would be too much for SRR. Just too much size. Even in Robinson's day when heavies were still 176-199 pounds, he still didn't try to venture into the big boys.

 

Marciano vs Joe Louis, Joe Louis may have been 90 years old, But he was still a capable fighter who was on an 8 fight win streak, Outweighed the small rocky by 30lbs exactly, And technically Joe Louis is one of the most gifted boxers to ever lace them up, If size truly did matter as much as these people say it does, Then Louis even in his advanced age should've easily kept the rock off of him and easily won a points decision or better yet knock him out with precise punching though this might not be possible considering how much his power had deteriorated. Rocky was exceptionally crude and yet the end result of their bout was Louis getting knocked out of the ring because of Marciano's sheer power. Not to mention rocky seemed to have an easy enough time pushing Louis around despite Louis having the major weight advantage. So we have a guy outweighed by 30lbs, Smaller by about 3 to 4 inches. and Had a reach disadvantage.

Alternatively if you use age as an excuse, How come no one in the 90s could knock down the old George foreman, Yet when George was close to his prime, Little Jimmy young managed to score a knockdown against Foreman? And I highly doubt anyone in their right mind is going to call George foreman a bad big man, I guess Jerry Quarry schooling Ron Lyle twice would also come into the picture. Marty Marshall former light heavyweight contender beating Sonny Liston in a decision