Everything in Aikido is hidden right out in the open. How much you can see is up to you.
You are talking about a number of years/ generations of practice being defined into the practice of Aikido.
Where do the movements come from?
How can they be used in other forms?
How do they relate to Pressure points?
What is the relation of movements to polarity of opponents?
What are the physical applications of movement?
What are the spiritual implications of clearing the mind of fear, darkness, turmoil to have clarity to act, or react?
Everything is right out in the open.
Aikido is just one piece of the martia arts puzzle.
Every martial art contains primary movements, and applications ... these are the secrets you seek.
Go get some pieces and find the answer to your puzzle.
I am still working on my puzzle, although these days it is looking pretty good to being more than half way done. I can see the picture in my mind, now if I can just get all the pieces to see if the puzzle is what I think it is ....