One thing I would disagree with article on, is that you can teach a follow through. They are correct that the follow through is indicative of previous parts of the motion. However if they focus on a good follow through it can clean up earlier faults.
If you've read my posts before, you've read that I focus on it. If the arm finishes too far from the post leg they had a lower arm slot and had a more twisting side to side motion. If the arm finishes near then post leg they had a higher overall arm slot are in more of a straight line motionand can control the pitch better.