I say make it a no contest. I mean the same thing happened to Fedor, cut by and illegal elbow and unable to continue. You have to name a winner so I think Jones plain and simple won that fight, it wasn't even the 12-6 elbow that cut Hamill and it was a dislocated shoulder from the takedown that made him unable to continue. Both great and classy fighters and both will move on from this and have great careers. It really doesn't matter a previous poster said Jon Jones will most assuredly learn from this and not use 12-6 elbows again. By the way, the rule is stupid because a horizontal elbow is more effective (and more destructive) than the 12-6 elbow. The rule should only be there for elbows to the back during a takedown which would leave a fighter possibly crippled for life. But to the face a 12-6 elbow is actually not as bad as the legal horizontal elbow because you cant generate as much force.
Boo! fight with Honor!