Re: Video definitions, "Aiki" and other terms.
I understand the conceptual relationship between "internal strength/power" and "skills" as often used in these discussions to be roughly analogous to that between "kokyu" and "aiki."
That is, they are related, but not identical, and while one concept in each pair of concepts refers to ways of generating power in movement, the other relates to employing power in a martial encounter in an effective way.
What I understand some of the "IP/IS" advocates to say about the difference between "aiki" and "ju" stems from whether the method of employing power in an encounter relies on/springs from an internal manipulation of structure, or in applying techique (waza) that manipulate the structure of uke through timing, leverage, etc.
This is where it seems the perception takes hold that timing, leverage, ma ai, etc., are of less value, since they relate to the "ju" level of the art and not what is treated as the higher, "aiki" level, despite the acknowledgement by virtually all that "jujustu" is a powerful and subtle thing.