70's heavies are grossly overrated. Grossly. Ali's physical peak in the 70's was Jan. 1, 1970. Frazier fought the best fight of his life on August 3rd, 1971 and never had a major victory again. No, a mess of Jerry Quarry does not count. Foreman was fed tomato cans, beat fading Frazier and chinny Norton then sank like U-Boat, going life and death with amateur Lyle and losing to Young. Post-Zaire, the division was a farce. Ali defending against Cooper, Evangelista, Dunn... robberies versus Young and Norton, getting so bad that amateur cruiserweight Leon Spinks won the title. Horrible, farcical, a travesty.
The golden age of bantamweights was the 1920s. That's still never been surpassed. Most often remembered as 1920 to 1929 but I'd extend it to a lengthy period 1917 to 1935, including Brown's full reign as world champion and included Pete Herman whose reign really probably signals the start of the golden age.