Agree with you here. Conn was one of the best light heavies and he was technically very sound as a boxer. I've talked to older fans of the sport who remember the earlier years of boxing, and they mention Benny Leonard as a very good technical fighter. Other than that, Harold Johnson and Arguello are two fine technical fighters. Arguello threw one of the most beautiful straight right hand lead punches that I've ever seen.
I have to give my vote to Johnny Persol, a light heavyweight contender from the 1960s. Watch him in his fight with Bobo Olson. There, Persol exhibited genius in the ring.
Ray Robinson was technically proficient because he could adapt to all different styles.If thats what u mean