Ah. If I'm reading this right, you're saying aiki could just be skipped. And yeah, it could. I've trained folks without it at times, and it loses a level of efficiency of movement and a set of options for recovery. Those aren't strictly necessary, but they are useful. If I was sticking to what was strictly necessary, I'd have to be prescient. Aiki training is really about developing options - I think that's most of the point of most training.