Seems like he might do well to me. However, I believe that the real reason for his mediocre career was because he did not fight according to what he was best at, which was said to be a boxing style, like in the vein of Holmes. Instead, being trained by his father, a legend of all people, he was taught to be a pressure fighter.
He may have had a better career. Even if he started there and eventually moved up to heavyweight after say, hypothetically unifying the cruiserweight division.
A lot of hindsight here... In the early/mid 80s the division was considered a joke. Although set up for small Heavies, it only really attracted big/lazy light heavies. Marvis would make no money fighting down there. It took a Holyfield to finally give the division a little positive spin, and by then Frazier was done.
This. Fighting at cruiserweight would’ve been a waste of time for Marvis, who was basically fighting on borrowed time considering how injury prone he was. Also, I think Marvis trying to get under 190 lbs without being drained in his early to mid 20’s is unrealistic, since Marvis carried 198-205 lbs very well.
I think Marvis could have had a productive career at cruiserweight, although I personally doubt him ever beating de Leon or Spinks, or becoming champion.
