Frazier's style did not lend itself to a peak performance with much longevity. The punishment he was willing to absorb at the beginning and mid-parts of his career sapped his reflexes and ability to absorb punishment as his career unfolded. This is just another way of saying that when his star started to fall it burned out very quickly. While his prime lasted, he deserves to Top 10, IMO, but if you extend the envelop to include some of his later losses against top competition you can make a case that he falls short.