Well, yeah, depends which Saunders we're talking about doesn't it? In form BJS matches two guys with significant stylistic similarities (and also weaknesses) of similar size - close to a 50/50 fight in my eyes. The Saunders who looked like sh1t against Akarov probably doesn't see the final bell.
If Saunders comes in at a 100% and Canelo fights him in his first fight at 160, I think it's a 50-50 fight, Saunders is not an easy style for anyone and he's naturally bigger and taller than Canelo.
i think saunders' (in-shape of course) size and movement would give canelo fits and he would make it the distance. if he can't stop a past prime cotto i don't think he stops a well-prepared BJS. i see canelo getting the decision against anyone whether he won the fight or not.
Canelo will knock his ass out, just like he did with the last two brits he fought
BJS is only keeping that belt warm for Canelo, and everybody knows it