That's true @palmerq, size isn't everything but I'm not basing it on size alone.

There were 2 versions of Ali. The 60's version fought by being fast on his feet and fast with his hands. He also had exceptional stamina so he could run all night and dart in to score and be out of range avoiding getting hit. But this was all heavily dependent on the fact that that Ali out-talled nearly all his opponents. He also outweighed nearly all of them too. You'll struggle to find an opponent in that time where he did not either outsize in some way. His success was dependent on his range as well as his speed. Later 70's Ali was heavier and stronger but his success depended on taking a lot of punches.

Conversely, Haye's range is more or less hum-drum today, and in fact the guys he fought at HW most all out-talled him and all out-weighed him! Completely different situation. Haye had to depend on real boxing skills, not having the luxury of a size advantage!

When Ali slowed down it showed the truth, Ali's reflexes absolutely sucked! He depended on running around out of range to be successful! He didn't have the reflexes or the upper body movement to avoid punishment.

Haye however fights on the edge, he has some of the best reflexes at HW ever seen and excellent head and upperbody movemet. He does not regularly get hit at all!

Taking punches like Ali did might have been ok in a featherfisted era like the 60's and 70's but I think you'd agree that today that would not be an advisable strategy! At the power of the modern division one would definitely need to avoid getting hit! Chins can only be so hard! The heftier the opposition, the greater the chances of KO. That's how much HW boxing has changed. The time of the punch bags is over!

And finally, Haye has real power at HW, Ali could not crack an egg compared to Haye.

And so that's why I give credit to Haye and not so much Ali. Ali's style would be good in the amatuers today but as a professional he would find things pretty rough, atleast in the HW division.

I mean if you actually analyse his career he struggled badly against some pretty poor quality opponents, Frazier, Norton, Spinks, Young. I don't think any of these guys would play any serious factor today. And how about getting decked by 185lb Cooper, do you really think Cooper would pose a punch threat to a modern HW? Doubt it.