Lewis would ice Dempsey early on or widely outpoint him. Lewis never got KO'd by fighters for whom he was properly prepared for and you can be sure he would be properly prepared for Dempsey.
I disagree, Lennox is quicker, straighter punches, actually has a jab and uses it and has a greater variety of punches in his ****nal. If he was the same size he'd outbox or KO Dempsey
If Lewis were smaller, he would be an entirely different fighter, not one to use space and distance as much. He would also be quicker and more mobile, less leaden footed. It's just silly to think a smaller version of him would just be miniaturized version of the real article.
Dempsey might not be the greatest heavyweight, but you would be hard put to find one better in a pound for pound sense. Bob Fitzsimmons perhaps.
I think Marciano proved more. He truly fought the best available and wasn't allowed to rest on his laurels. I think Tyson had the same career arc as Dempsey (without artificially extending it though inactivity) and did it more impressively. I just don't put a lot of stock in the row of hasbeens Dempsey knocked over and in his great dethroning of an old, inactive and not-very-good champion. He seemed much more on an accomplished opportunist than champion.
Lets say that Marciano was greater. That doesn't make him better pound for pound. He generally needed to go to the score cards, to bet his Fulton's and Willard's, and of course he was bigger than Dempsey! Lets look at this from your perspective. When will we next see a 185lb fighter, exploit a weak era to destroy the old/fat/inactive super-heavyweights? The time would not be bad right now!
You could take it every single common opponent of Dempsey and Greb and Greb would still be a hall of famer.