Re: ALI's (Possible Opponents 1967 thru 1970)
I've always said we never saw Ali in his prime (summer of 67 to summer of 70)
Many fighters you mentioned would have been in that time frame of mix.
He would have been a monster:
Bonavena was on the table for the summer of 67.
Spencer would have been iced before mid-68.
Leotis would have been iced before mid-68.
Mathias would have fallen like a giant oak.
Quarry would have been brutalized in 68 or 69.
Ellis would have been a boxing match beat down (much worse than July of 71) in 68 or 69.
A Frazier fight...probably would have been held up until mid-69 and....tho a tough scrap, Ali would have put the stoppage on him in the late rounds at that time IMO.
We may have also seen a Peralta title fight from Luna Park, Argentina sometime in 69-70.
Be ye for or against Ali, he (by his own efforts) never let us see his prime potential.