Max Baer, Jimmy Braddock, and Jack Sharky were all ex-heavyweight champions who are impressive feathers in his cap.
Everyone rags on Carnera but really his only faults were a lack of power and a relatively soft chin. He had a decent jab and some good skills for his size. Max Schmeling even praises his technical ability in his autobiography. Think of Carnera as a McCline, a huge guy who didn't have one punch KO power, though with much better heart and fighting spirit. He was a weak champion, and he did win many of his fights on fixes, but he was a very strong man with a solid grasp of the fundementals of the sport.
Hell even guys like Buddy Baer and Tony Galento were tough, hard punching (in Galento's case, steel chinned) contenders who were the Samuel Peters of their day.
Joe Louis fought from the mid 30's to the late 40's, and unlike Tyson he fought the very best contenders throughout his professional career. Louis even fought a future top ten heavyweight champion in his very last fight.
Not what I would call an unimpressive resume.