I hadn't heard of Jay Berger until his name came up in another thread the other day with him talking about quickstart. I watched that and another video of him on youtube where he was presenting a drill (presumably at a coaches conference). In the drill he was working with a player to not 'back up' but to stay on top of the baseline to contact the ball and at one point told him not to take a drop step to get his back foot lined up with the bounce (which incidently led to the best shot the kid hit in the video).
Show this vid to any Spanish coach worth his salt and he'll laugh his *** off all the way to siesta! The whole Spanish system is based on getting the body behind the ball.
So, while I don't know who this guy is, if he has anything to do with the future of American tennis, I wouldn't be putting my mortgage on him producing any players.