I have gone back & forth on this fight so many times.
It's difficult to get a "read" off of it & I keep flip-flopping, but at the moment I'm swerving towards GGG in a (relatively) dull fight. If GGG boxes behind his jab, I don't think Canelo is technically proficient enough to find the positioning he needs to set up the combos he needs to win (those kinda squared-up three-four punch barrages then up to the head with the left hook that he likes to throw inside).
I just think Alvarez's feet are much, much too clumsy to deal with a jab like Golovkin's, & I'm relying on the old guy to have enough legs & for his punching to have enough impact to keep Alvarez honest. If Golovkin doesn't take too much damage from the occasional burst Canelo does manage to get through with, I can see GGG taking a decision, something like 8-4 or 9-3 (wide enough that it'd be a particularly egregious robbery if they scored it the other way).
To create the openings he needs where Canelo can do that work, he's gonna suddenly need to develop twice the stamina that he's shown in other fights, 'cos GGG isn't gonna be sprinting backwards like Lara or pinging him like Trout, he's gonna be thudding his head back like a Pez dispenser every time he lands. Facing a natural counterpuncher, I can just see GGG going "Come on then, find a way through this", & I don't think Canelo is good enough at that game to get to him.
This, however, is how I feel this week. I'll probably feel different by this weekend, & different again the week after.
PS: As the recent multi-million dollar sparring match has probably lowered the collective IQ of all combat sports' fans, if only via osmosis, I should add that I am super excited for this fight, even if right now I don't see Hagler-Hearns II.