Nothing wrong with wanting to build a better mousetrap. And if I ever have a chance to try out any of those, I wouldn't pass on the opportunity.
And I get what the guy in the vid is trying to accomplish. Obviously, for the purpose of bodybuilding, the sit-down versions would be more ideal.
However, if the purpose of his design is to better mimic the various athletic motions, then he should design some of the machines in stand up versions (for example, the throwing patterns machines). His leg machines in the vid better accomplish this as they are performed standing up.
For the purpose of translating strength gains on to the playing field, the athlete MUST learn to transfer force from the ground. How often does a quarterback or pitcher throw the ball sitting down...? The ability to train and exploit the posterior/anterior oblique subsystem is vital.
Again, I applaud the guy for wanting to build a better mousetrap. Truth be told, however, an understanding of biomechanics/anatomy, a moderate investment at the local hardware store, some good quality bands, and INGENUITY can accomplish very similar objectives - in a more cost-efficient and logistically feasible manner. I've incorporated training like this for the last 3 years and I continue to get stronger and stay injury free.