Amen to that. What you are doing with the feet together is locking down the lower body so that your upper body can only turn back and through. The lower body cant through you left or right or up or anyways, all of which are false movements

In fact its a real good way to learn. Hit 50 balls with your feet together until you hit the ball straight consistently. Then space out the feet a little at a time and work on keeping that lower body just as stable (by either tilting the hips, kicking the right knee in or whatever)