I'm not going to get into, but you can line up three people and have them all do -what looks like the same movement- and they are not all doing the same thing. I have had people touch me and they feel instant kuzushi and they do not understand how and why it is happening. Just for starters I can talk about intent, and "when one thing moves, everything moves" till the cows come home here, yet from my experiences I haven't met anyone in the art of Aikido who can do that to any serious level. I see some shihan trying. So I am really not inclined to debate how just that will change someones quality of movement in a way that cannot be seen. Now we can add in what you are moving and how and what is connected, but most everyone is going to feel just like your average athletic gym member doing martial arts.
Are you saying that intent and "when one thing moves, everything moves" imply each other, or that they are two separate but mutually supportive skills? I guess I am confused what you mean by "change someones quality of movement in a way that cannot be seen", but shouldn't the whole body movement part be noticeable to the observer? Do you feel what Rickson Gracie is doing there is useful for building one, the other, both, neither, or it depends?