Right now I would say Abner Mares, the kid has an impressive streak and has by far a better resume than Chavez Jr or Canelo.
The opposition of Canelo has been absolutely terrible, and while Chavez Jr already lost, at least he fought one of the best P4P boxers in the world. There's no shame in losing against Maravilla Martínez.
Canelo on the other hand keeps avoiding even decent competition, hell, he's avoiding any competition at 154 lbs and decided to fight against guys that are WWs or LWWs.
Barrera, Morales, JMM, Sanchez, JCC Sr, all those guys had or still have great skills and faced the best, while Canelo hasn't done shit. I don't care if he "was going to fight" Wladimir K or something like that, until he does it he's still an unproved fighter who has a paper belt.