While I enjoyed the read, "regression" is more of a adjective or label placed I would put on everyday players. Everyone loves to get caught up the numbers now days, metrics this metrics that, but you still have to throw a round ball and hit it with a round bat. Mechanics are as number 45 has shown extremely important, just check out video of Vance Worley since he left. 2 video's you posted though Parker are 2 different pitches. 1st vid you can see he overthrew it, trying to bust inside and became out-front, out of balance. 2nd vid very controlled, cutter that froze hitter, excellent pitch. Number 45 gained a lot of the biggest factor for pitchers and that's confidence and his stats show this. Will he regress to bad mechanics? I'm on the side he wont and will live up to extension.