If you've never seen his fight with McCallum, then how can you judge him simply based on the Nunn fight? He also schooled Barkley, and Steve Collins.
Past: Willie Pep Pernell Whitaker Nicolino Locche Ricardo Lopez Harold Johnson Ezzard Charles Sugar Ray Robinson Jose Napoles James Toney Mike McCallum Alexis Arguello Underrated master boxers that people forgot: Sumbu Kalambay Donald Curry Orlando Canizales Miguel Lora George Benton Alberto Davila
There's ****ing loads. A master boxer is someone who's either a master at the one style/their style, or a great all rounder. It's subjective. Benny Leonard Charles Pep Benson Gans Tunney Ali Napoles Pea Buchanan Duran Locche Mcallum Hagler SRL Toney Mayweather Hopkins etc etc