What a great post. There are other major problems with the swing you describe, but I didn't realize until your post that it affects the head in that way.Hey FP I appreciate what you are saying about the above posted clips. The reason the players are able to keep their head in with an over rotation or thrown shoulder is their hands.
Now before you think im insane lets look at it from a mechanical view of things. Both hitters achieved separation of the hands or walking away from their hands. Their hands therefore became an independent moving part of the swing.
Do a drilll and tell me your thoughts. Look at yourself in a mirror, face to face and look down at your shoulders. On the outside of your shoulders lets call it the shoulder plane.
First start with your hands inside of the plane of the shoulders then rotate letting your shoulder fly out and watch what happens. The head has to follow the shoulders. Why?........... because we let the shoulders turn the hands and made it one unit.
Now walk away from your hands and rotate and youll discover you can get alot more open and the head can still stay on the ball with a ton less strain on the head eyes and neck.
with proper separation you can rotate the belly button past the pitcher and still keep the head in there. Letting the shoulders turn the hands........... not so much.
Most kids i see hit only a very few at the college exposure level or heck even at the college level its self know the importance of separation or how to do it.
This is why I believe we see what we see from so many kids, as the shoulder comes out the head follows.