I have him at 16. In a pure historical sense, his two fights with Joe Louis may have been the most consequential in history, in relation to providing a compelling historical side backstory to WWII. He was also probably the second most accomplished HW of the 1930's, behind only Louis. Also was a friend to Joe Louis after their career's ended and a mentor to the Klitshcko's. Had some bad losses on his resume and wouldn't hold up H2H, but a great in era fighter with incredible historical impact.
Defeated prime Joe Louis. Huge achievement. Some put Frazier in their top 10 because of the FOTC. Schmeling is in my top 25.
Beating an ATG doesn't make the victor an ATG. It does not take an ATG to beat an ATG. McCall and Rahman are proof of that. As is Buster Douglas.