I think one of the more common problems people have in picking up what he is showing is that they don't take him literally when they should. Between the language barrier, and just a lack of a common vocabulary when discussing concept I think it's tempting to think that he's talking in metaphor when sometimes he is not.
I've noticed this with a number of teachers. Every once in a while, the light bulb will go on and I'll realize that when Sensei said X, that's exactly what he meant. Not a metaphor, not a visualization, just do X.
Which is why this stuff (aikido in general, not just IP) is so hard to do, and to teach. Once you get it, you realize that it was right there in front of you the whole time.