The key principle of what I teach is just what I think your thinking about. Development of control of the bat. A consistent swing plane to the ball. It is IMO the single most important aspect in the development of a young hitter.
There may be others on here who will disagree and that is fine with me but if the swing plane is consistent the hitter will be making much better contact with the ball when they get on plane with the pitch.
There are of course a lot of elements that must be developed in a hitter to get to that consistency but for me that is the goal.
Dana
A good clean swing plane is a big deal.