He definitely doesn't have a high release point in his highlights. That could've already been corrected or worked on already here, who knows. He throws away from his body a lot, while dropping his shoulder and moving his throwing hand out to his right. It's a slow release, but again, it could've been worked on and changed since he got here.
Highlights show all of that. I don't think anyone, at least anyone with even a rudimentary grasp of the game, expected him to come in and start right away. Yes, it's only a small collection of his entire body of work in high-school, but that's his best throws. I wouldn't expect other footage to show these clips up.
I should add, his mobility doesn't worry me. He moves as well as most that size. I don't expect him to be mobile as ****. He's no Brad Kaaya on his feet or even close to that level.