Defensive boxing ability itself, no. But PEDs would allow for conditioning to sustain peak defense for longer periods of time.
Why are Mexicans such a big draw and he made GGG miss most of his punches, he countered very well also.
Canelo is better skill wise than AJ, even Hearn has stated that AJ hasn`t peaked yet and p4p he takes a far better shot than AJ does, GGG is a hard punching middle and Canelo took and rode his shots very well while we`ve seen AJ hurt and on the verge of being stopped, a heavyweight with the ability of GGG would clean up, fact.
Very good defensively and has pretty good whiskers too, which never really get factored in to a good defense.
I'd say that Canelo has a really top shelf defence. There was a recent GGG / Toney thread where a comparison was drawn between Toney and Canelo. Studying the two back to back I honestly felt Canelo was a little bit better, and Toney was freaking good. Canelo's reflexes are something else, he can react at almost the point where its too late to move, and do just enough to slip a punch and still have enough time left to counter. I thought that his cement feet were going to sink him vs GGG but he's plugged that gap (unfortunately for us that wanted a proper fight) and demonstrated excellent mobility last time out. He's also clearly got a much better beard at 160 than the lighter weights. His main vulnerability is to the jab, and Golovkin fully exploited that hole. I also think that he won't be able to protect his body as well as his head if GGG commits to a body attack.