For that, we might have to go back to Louisville, Kentucky, and bring forth Joe E. Martin's Cassius Clay / Muhammad Ali (before Cassius / Muhammad saw that Kangaroo fight).
A lot of people don't think very highly of Willard, and the same people may or may not respect Jack Johnson. They almost certainly respect Ali, but understand that his decline was brutal. I like my question better!
Ageless wonder Willard would have 50 years to fine his skills to beat Ali. I think it's fair to say that he'd learn a thing or two throughout that time. How did he lack physical traits? He was much bigger than Ali and by all accounts, very powerful man with excellent stamina. He was a good athlete, just not very skilled boxer.
I don't think it's reasonable to think that way. We're talking about someone who was huge and quite athletic, not some kind midget. He didn't look clumsy against Johnson, only slightly crude.
Dad Bod, Jab pushing, bandy legged, clumsy oaf Jess is so uninteresting that fantastic boxing writer Adam Pollack is doing a book on every heavyweight champion through Dempsey and he decided to skip Willard! HA! That says it all
He also refused to spar with black boxers. Kind of difficult to compete against guys with whom you haven't trained for their style.