I agree, Walcott was a counter puncher with amazing footwork. That's not how Ali fought. I actually don't think that Ali had more advanced repertoire. He was better than Corbett at what he did, he was also bigger and more durable but Ali didn't use punches or combinations that Corbett didn't. Ali was far better fighter than Corbett but their styles are very similar. A lot of clinching tactics (Corbett was quite strong for his size) and beautiful footwork. Both also fought with low guard and relied on their speed heavily. The difference is that Ail could good beat fighters even without his speed due to durability and Corbett couldn't.