whether it can be articulated by its chief practitioners in terms that make sense to me (without lots of metaphysical hyperbole) - yep, western rationalist/empirical/scientific model from the outset, lots of use of CMA/JMA terms but whenever a definition and explanation was requested (lots of Q&A throughout, very helpful) a cogent one was given. I don't pretend to understand it all nor to be sufficiently well versed in anatomy, physiology, sports science, etc. to have an expert opinion but there's clearly a really solid model and a lot of profound skills that go with it. If anything the testimony and skills of the longer term students is the most convincing evidence since this suggests the stuff can be taught and lead to improvements in one's chosen art(s) in time-scales measured in months/years rather than decades.
That's what appealed to me about Dan's teaching when I saw him earlier this year. Not much mystical stuff (in my opinion there is a place for that, but this isn't really it), just a set of exercise drills and a clear, progressive rationale underlying them. You basically start with a repeated sequence opening the body in the six directions, then when you have enough sensitivity and body connection you can start working on developing yin-yang and spirals.
Some of the more advanced concepts still escape me, but I have been practising this stuff daily for six months and can feel big changes already in how my body moves.