Re: ALI's (Possible Opponents 1967 thru 1970)
I think there's a real possibility Urtain could be added to that list. He was hot until Cooper got to him in November 1970 to regain the European Title. With his win in the first Blin fight, the physically powerful Urtain proved himself over the championship distance, and the EBU crown could get the holder a shot at Ali.
Henry Clark might have been interesting. He was the first heavyweight contender to openly idolize Ali, shared Muhammad's stature, was durable, and had decent skills. He could well have been the first challenger for Ali younger than Muhammad himself. (Even during his second reign, Wepner and Lyle were actually older than he was. Bugner was the one really youthful challenger he had during his prime.) Only Terrell and Chuvalo went the championship distance with Ali prior to the FOTC, and Clark very possibly also extends him the limit.