Absolutely. Prime Frazier is a much better fighter than Liston and he wont freeze like patterson. Frazier is not giving away so much weight either.
Liston was avoided like the plague by the 60s up and comers. Frazier, Quarry, Bonavena. That being said, it would be an interesting fight for about 5 rds. After that Listons age would begin to tell.
As the other poster said, are we talking a 1970 fight or a prime vs. prime? The answers here are confusing. I think a prime Sonny beats a prime Joe and that's taking nothing away from Joe's GREAT legacy.
A peak Frazier with a referee that didn't let Foreman push Joe into position would have a shout, I think. In 1970 he batters Liston. Peak for peak, a great contest, we never saw what Sonny could do with anybody like Frazier, if he could time it and catch him with the jab, then big rights, well it's over but.... if Joe can get inside enough to land the hooks then it's a war of attrition and there's only one winner in that.