I highly doubt there'll ever be a champ as dominant as Louis was. For twelve long years there was no question about his status as champion (maybe minor rumblings until his rematch with schmellimg). Wlad is quite dominant now but there is the dispute of vitali. In today's world it is gonna be very difficult to see a truly dominant champion again. To unify every claim and make 25 defences. Amazing achievement.
Joe Louis in his time was so dominant a fighter ,it is hard today to feel what the public felt about him in those days the 1930s and early 1940s. His name evoked a combination of awe and love . He was the "grim reaper". A threshing machine in the ring...
Sugar Ray had to move up in class because he knocked everybody out, But it doesn't get any worse when a champion has a bum of the month club. Wladimir also deserves a mention.