I would be blown away if Kanter doesn't improve substantially coming into next year and/or given an amount of minutes that he can actually do something with. Coming off the bench and just being expected to produce and contribute is a tough gig. There's a reason Sloan liked having certain vets like Harpring come off the bench, and it's largely because going from sitting down to suddenly being thrown in the fray and being expected to contribute isn't easy.
Kanter has some things he needs to learn:
-Quick moves: Most young players need to learn patience, Kanter's a different animal, though. He's stronger than anyone he's faced not named Nikola Pekovic, he can get position. If he gets position, he should be prepared for a quick jump hook, layup, reverse, or get to the line. His offense shouldn't be predicated on a protracted siege, that's bad for the offense, and that helps the D. Can some simple moves and really pressure the defense. Move away from the ball-stopping.
-Court awareness/passing: Watch that video that has Shaq, Chuck, and Kenny as Hakeem. Learn the place on the block that he wants and needs to be. Use that so he can do quick surveys of the defense, and so that he knows who he can kick to if the situation reveals itself. Move away from the ball-stopping.
-Picks: So much good offense is based on setting a good pick. I wouldn't say he's bad, but he's not fluent in turning his pick into a weapon for himself as either a PnR player or a pick-and-pop option. A lot of that comes down to coaching and the ball-handler, but he should still work harder on setting stronger picks, rolling faster, and also slipping picks and sliding to the basket quicker. Also can a couple mid-range Js. Move away from the ball-stopping.
All of these things would set up his up-and-under if/when he wants to use it.