Actually, there's some rumors that he has a leg injury. If true, it MAY be affecting his ability to push off or plant, depending on the leg.
Have you noticed how he gets up limping, after what seems like every time he's hit or knocked down? I feel like I've watched him do it once every game.
It could even be the hip injury from back in September lingering. I think the thing to watch for is if he has some minor surgery done right after the season. We'll see.
Personally I think most of his sidearms and awkward motion stuff has been attempting to get rid of the ball quickly when he's going to be under pressure (alot more than most realize). Also it seems like he does it when he seems an opening and his feet aren't set - for this there may be a better solution, but who knows.