What about Ken Norton? I would say he was a fine technician. Even Ali and Holmes couldnt beat him by more than 1 point.
Jersey Joe was more cute than a technician. Obviously, his technique did not save from many losses. Joe Louis had the greatest offensive arsenal presented in the division. For their respective places in the development of the sport, Corbett, Johnson and Tunney rank high. Also, I would like to mention Riddick Bowe, who for a short while demonstrated great skill and technique, good at distance and really good in close.
He suffered the whitaker syndrome. Alot of judges didnt like his style, but in actuality he was clearly outfighting his opponents. too much walcott waltzing caused him "in the eyes of judges" to lose the louis I and maxim I bouts, but according the nearly every ringsider/newspaper/fan poll walcott clearly deserved the decision.
Obviously Golota-He combined handspeed, a great jab, some power, and extensive knowlededge of the weak points of the body unlike anyone else!
what about sonny liston? according to many great sources he was excellent at both boxing and going on the attack.
I doubt anyone will agree with me, but i think that Rocky Marciano is the most purely technically correct boxer. His guard was always high and in the correct position. He always put 100% of his body behind every single punch. His footwork was sound. He wasnt as fast, as accurate or as flashy as many others, but he was technically better than most if not all, imo. It makes sense too. Physically he wasnt the most gifted ever, yet it is arguable that he was the best hitter, the fittest etc. I believe that most of his attributes were enhanced, because he was so technically good at the style he employed. Which is, incidentally, probably the most basic, most successful and the most commonly taught style of boxing.