Hardly. Wallace Bud Smith was worse than mediocre. Kenny Lane wasn't quite a lightweight, and was a 13-5 underdog against Brown, which shows contemporary opinion about him was pretty low. Dave Charnley was 12-5 underdog for first bout, mediocre European champion. Paolo Rosi, Johnny Busso? Ralph Dupas wasn't a lightweight either.
Yes, and Henry Cooper was an all-time great, right. Charnley was on Cooper's level, great in Europe, but completely disappointing at world level. Mediocre.
Let's begin by remembering that he is a member of the Hall of Fame. He won the title at a time when the weight category was a virtual who's who of boxing greats. And he held that title for several years until he met up with Carlos Ortiz (another HOF member) - but then, he was getting on in years when they boxed. The problem was inconsistency in his boxing. He lost many matches that he should have won. I've read too little of his bio to know whether it was a matter of attitude, disruption of his career by WW II, poor management, or possible other personal matters. Perhaps it was a combination of all these things. Still he won well over 100 fights, held the title for a long time until he was defeated by another HOF member, and, if i recall correctly from past readings, was ranked among the Top 100 of all time.