Ali didn't look so surperior versus aggressive sluggers Frazier and Chuvalo. He was competitive against Frazier, but lost, and though he did pretty much shut out Chuvalo, he just couldn't keep Chuvalo off of him.
If you have Ring mags and follow other press clippings, then you would know that Ali had a HUGE surge of press and public support after the Foreman fight. Prior to that neither the press nor boxing oldtimers were especially impressed by him. He was considered a loudmouth with a shaky chin when Liston took what he considered a freebie. At Ali's 66-67 peak it was acknowledged that the division was weak and nobody could be found to beat him, weak praise.