It's like with the CXW video, I agree he's got some real ability showing his stuff there, but that won't make him a better tennis player, and the skills that are universal to his training, and would help him with tennis, are sills that the tennis players are already aware of, and have good methods for practicing.
What I get from the above statement is that you believe there is only one model of human movement, that both CXW and world class tennis players operate within that model and seek to optimize movement within that model.
In my opinion that is not true. There are at least two models of human movement (using very broad strokes here): the modern Western physiology/sports model and the Eastern internal arts one. They are mutually exclusive. Optimizing movement in one model will yield results unattainable in the other and vice versa. Both result in some incredible feats for the untrained person.
You can think of these two models as two mountains. Walking up one of them (i.e. optimizing within that model) means you won't be walking up the other. And that's why people keep saying IP requires a fundamentally different way of movement: because it does.