I have experienced what you are talking about. Even if you're standing still with your center, pulling the shot stick away from the basket, you'll get that funky shot that misses. It's like you're being sucked into the defense.
These animations happen around the top of the key way to often even when trying to avoid contact, so I agree that a center should still be able to perform his move whether it be a fadeaway or a hook shot. Just make the shot success lower if a defender is in front of the offensive man. As it is now, you'll have way more success posting up with or without a dribble. Those funky animations don't happen if you're doing your moves from the post.
On the flip side, if you go baseline, you get very little contact going to the paint, even if there's a man right in front of you.