That's a common view in Buddhism generally, not just in Japan. That the path to enlightenment leads through mindfulness and meditation, which can take place in the context of many many outward forms.
Okay, so then to me it appears possible that the BABS (Bad A$$ Body Skills, let's stay away from "IS" and "aiki" for now) of Takeda, Ueshiba, Sagawa, Yoshida, etc., could be a path to enlightenment or not, depending on how the training was utilized.
I guess where I am going with this is that there seem to be two possible interpretations of aiki around the aikiweb forums:
1) Aiki = Bad A$$ Body Skills
2) Aiki = A process of enlightenment utilizing Bad A$$ Body Skills as the vehicle.
But there may be other, better ways to parse this out. Any other options anyone else can think of?