Dr. Wagner Jr. is the top tecnico not wearing a silver mask in CMLL. He's a young legend to the fans, a wrestler with international experience (and success!) and capable of a great match when he wants one. Dr. Wagner is one of the most popular wrestlers in Mexico, and an iconic figure.
Wagner turned tecnico following the death of his father. The change was fan inspired; Wagner was in a four way mask match on the first Arena Mexico show after his father's passing, and the fans did not want him to lose his mask that night under any circumstances. Wagner did not lose his mask, and the crowd clung to him after that moment. Wagner and the promotion tried to go back to the status quo after, but the fans cheered him enough to make a change.
Dr. Wagner becoming a tecnico had ripple affects across the promotion. Since he was feuding with Canek, Canek had to turn rudo to continue it. Later, in 2005, the fans loudly picked Wagner over Atlantis when they were setting up a mask versus mask match, to the point where Atlantis was tainted as a tecnico (and had to be turned rudo) and Wagner had become so popular, the match couldn't be done at a profit to all sides.
Even though the mask match never took place, Atlantis and Wagner continue to be rivals, with the idea all sides might one day do the match in a different arena where the money works out better. (The feud with Canek has slipped to the wayside.)
More pressing for Dr. Wagner at the moment is a feud with another recently turned tecnico, LA Park. As with Atlantis, the crowd turned on LA Park with no prompting, and he responded in kind. Wagner stuck up for the people of "his house", and he and Park have had violent brawls in the weeks since. A Park/Wagner mask match would seem to have the same financial issues as the Atlantis one, but that's the way they seem to be heading.
Wagner often teams with Mistico, as a big brother/protector to the smaller wrestler. He'll also team with his newly unmasked brother, Silver King, who has been wrestling in some locales as Dr. Wagner Jr. II or el Hermano de Dr. Wagner Jr. Wagner has shown himself capable of wrestling Japanese junior and lucha technical styles, but his current feuds and positioning has resulted in him primary working as a brawler with hot comeback moves.
Dr. Wagner Jr. still potentially has many years left in his career. However, he's often said to have saved well from his career and could retire early. It's believed he was going to lose his mask to Atlantis when that match was originally scheduled, which could have been the one last big payoff of his career. Instead, it seems like he's going to hang around for a while longer.
