The writer blows off "Kokyu" as being central, but then he goes on to say in his last sentence:
Isn't aiki (and jujutu in general) as well as CMA the art of mastering jing but expressed in different contexts?
The problem is that kokyu is simply jin, at its core, yet the writer thinks kokyu is some kind of normal-physical power, it seems. As the old saying says (and I've mentioned this a number of times in the past): "There is only one jin. All jins come from the one jin". So kokyu, "fa jin", "aiki age", aiki itself (which is an application; kokyu is a ryoku), etc., etc., are all based on one power. If you learn how to do that one power and then learn a number of its sophisticated usages, you can use them in numerous martial arts, despite the many various terms found in many various Asian martial-arts for that same basic jin-derived power.