I'm not worried about Kanter. Looks like strength/energy is his problem right now, which hasn't been a concern in the past. He should be fine, even if it takes a couple months to get into playing shape. He's doing a good job of getting position, securing the ball in the post, and making his reads before backing his man down or facing up. He throws in quick moves occasionally to keep the defenders guessing. He still has a bad habit of forcing shots up when he's surrounded (which is happening even with loads of time on the shot clock...), but that should be correctable.
Derrick's forcing everything. Not making reads at all. Just puts his head down and plows ahead. Ugly.
I agree on this. Favors is forcing way too much. However, Kanter being out of shape won't fix his defensive issues. But I think he will improve with time.