Some old time Heavyweights were not that small

Very true, the Klitschko brothers are very big and very good. Take them out of the picture and you can see why you really don't need to be huge to compete with the rest of the best these days.

Haye and Adamek are probably #3 and #4 and both moved up to HW.

Being "not huge" is still being a hell of a lot bigger than some of the better HWs of the past.

Honestly, Chris Byrd would have been able to bully some of these guys.

A guy like Holyfield who was considered a small HW during his prime (6'2 1/2" with a 77 1/2" reach and 205-210Lbs) would look like a monster compared to guys like Dempsey, Tunney, Schmeling, Braddock, and others. Max Baer was considered huge but was just a little bit taller with a slightly longer reach and about the same weight as Holyfield. It's not just about height and weight... you have to consider how it's all put together.

I feel that you need a little height, reach, and weight to compete with most of the modern era. You don't have to be extremely huge but if you're under 6' and 200 Lbs... (6' and 200 was considered a big HW once upon a time... think Jersey Joe Walcott) I really wouldn't advise it unless you are exceptionally talented.

IMO, guys like Ali, Holmes, Holyfield, and Foreman had the right combination of skill, size, and durability to compete with any HW ever regardless of size. Norton was in this size group as well but wasn't quite the "total package" that these guys were... because of this, there could be situations when his lack of size or durability would cause him to lose vs. a really big HW like Bowe, Lewis, etc.

Louis is no doubt an all-time great fighter. He was a little smaller than guys like Ali, Holmes, Holyfield, and Foreman and I don't think he was as durable. These two factors keep him behind the mentioned 4 in H2H discussions... but I do have him at #5.

So, all in all I will say that size isn't everything but it is a big factor if a guy with size is a talented fighter. All other things being equal... size matters.

 

These would all be considered small these days, except willard, and most of the big heavyweights around in that old past eras were not that good.they were probably mainly attraactions

 

http://www.la84foundation.org/SportsLibrary/BBM/1914/bbm4j.pdf

With the possible exception of the 1990s and to a lesser extent the 70s, it really does seem that throughout history the bigger the contenders, the worst the era is perceived. What this means, i am not sure, but i do tend to think that when the skills and standards are lower, the physical attributes become more important and the size of challengers will naturally rise. If this theory is true, we pretty much peaked in the 70s or maybe the 60s with Joe Frazier and it has been down hill ever since!