The key to getting the ball down in the zone is to get on top of the ball. Obviously, easier said than done. But as a HS pitching coach, I have to evaluate a bunch of kids with horrible mechanics that their summer coaches have taught them. Getting the ball out of the glove is the primary thing do and to do this right, a pitcher needs to do this. Keep the glove and pitching hand down by the belly button. By doing this, the throwing hand has to "go up" which makes it easier to get on top. DO NOT LIFT hands with leg lift as this will make it difficult to get on top quicker and not lag behind. The less motion, the more liklihood to be able to repeat the mechanics. I haven't seen his motion and cannot comment exactly what he does, but I bet his hand placement could be better as well as his motion itself and make it more compact.