Well, thanks for taking the time to make the videos; I hope the discussion becomes fruitful.
Your first video has a lot to do with timing and I think timing is critical in most encounters, whether they are "aiki" or not. So while I agree that there is "timing" in aiki, I don't think it is particularly defining of Aiki.
Besides, we have something like this from Ueshiba: " I asked someone at my side who this person was. It was explained to me that he was the famous Tenryu who had withdrawn from the Sumo Wrestler's Association. I was then introduced to him. Finally, we ended up pitting our strength against each other. I sat down and said to Tenryu, "Please try to push me over. Push hard, there's no need to hold back." Since I knew the secret of Aikido, I could not be moved an inch.
Obviously just standing still to Tenryu's push is does not really have a lot to do with "timing", so accepting that there is timing in most good techniques of any martial style, it looks like your ideas about "structure" are perhaps closer to the point the Ueshiba was talking about.
However, while I think you're going in the right direction, I don't think you've gone far enough. Your comments on structure and spine, etc., are a start, but they don't encompass a next-step like this one:
In the above picture the comments about spine, etc., begin to go by the wayside because there's more going on than just 'structure'. Further down the road, it gets even more complicated because 'structure' (as you're speaking of it) only plays a minor role and the mental menipulation of force vectors becomes the dominant factor (the Divine Will, as O-Sensei put it) and mental manipulation of those forces so that they combine with forces from an opponent become more of a focus. Don't get me wrong... I'm not saying that some of the things you mention never come into play, I'm just saying that at a more sophisticated level things are, well, more sophisticated.