...he had n't been unjustly banned from boxing 1967-1970 ? I envisage that he'd have been at his very best circa 1969-71,providing he'd kept his motivation. Just before his exile,there were talks of a second fight with Floyd Patterson and one with Thad Spencer. Both of which he'd have won easily. He could still have had a trilogy with Joe Frazier,but in this reality,I could see him winning the first and third,and losing the second very closely. My reasoning is that after beating Joe in their first one,he'd get a bit complacent,then regain his focus for the rubber match. Thoughts ?
Id agree with you regarding Ali peaking from 69-71, that would be age 27-29, seems about right when you compare the 67 (age 25) Ali to the 71 (age 29) Ali. He would have gained more experience & improved but would have still kept the fleet footedness & handspeed until about 30 probably, he would have gradually slowed in footspeed but at least he would have been active, therefore I imagine that even at 29 in 1971 he would have looked a little smoother than he did vs Joe, its not like Ali`s style allows him to take damage in those 3/4 yrs he had off, the activity would have kept his sharpness.
There is a chance that he had actually peaked in 1967, especially when you look at how he was vs Terrell & Folley but at the very least I think he could have maintained that form until 1969... Id bet on him improving tho, he seemed to improve almost every fight & he was a really dedicated guy, he had to be to get that good.
Physically, I feel that Muhammad would have been at his peak between 1968-1970. But his experience (that he would have gathered) and ability to adapt would have still seen him fighting at the same level of effectiveness (though in a somewhat different way - style wise) till around 1973.