No doubt,he cleaned out a very good heavyweight division easily from 1958 until Patterson.Liston's prime was as good as anyone's. Skills and resume wise.
Liston was past his prime when lost to Cassius Clay in 1964.Plus he had only fought 6 rounds in the previous 3 years.That's two reason's Liston got tired.He had no problem going 12 rounds in his prime.Just watch his fight with the highly skilled Eddie Machen.
Your right,Liston had it all.From his great left jab,84 inch reach,KO power in both hands,and his granite chin(Everybody knows he threw the 2nd fight with Muhammad Ali).Liston also showed great heart in fighting with a broken jaw early in his career against vetern Marty Marshall.Liston was hitting Marshall so hard in the 10th and final round,that Marshall stepped out of the ring!
I believe Sonny Liston was the most underrated Heavyweight Champion of all-time,and i have him very high on my top 10 HEAD TO HEAD heavyweights of all-time.