The coordination is primary, the positioning is not. I would not read too much into the external appearance of it, since that's not really the goal of it at all.
I agree the positioning is not the goal, but if the positioning were irrelevant, why would he give detailed instructions about his "oblique T-step"? And why not have a different positioning of the feet? Or perhaps Yao Chengguang (not that this stuff is originally his anyway) is smart enough to place his feet in such a way that he can most easily achieve his goals in practice?
I may not be all that knowledgeable about this internal stuff, but often plain old logic can get you a long way.