Each technique is another clue in the puzzle. A jigsaw piece in the big picture that is aiki.
Clue to what? A clue to what is it that Tomiki was trying to communicate to us? A clue to the ri-ai, or the internal logic of the kata and to the system as a whole.
For instance, Sankata at first appears to be a huge, diverse pile of situational defense techniques preserved from older aikijitsu, but after playing a while it becomes apparent that you are working with varied distance conditions. Yonkata also looks like just a pile of techniques but it is obvious from the beginning that it has a different spirit to it than does Sankata. Yonkata is a wrist release kata, exploring seven ways to release a wrist-grab, seven things that happen when those releases screw up, and a pile of techniques that can occur from those situations. Rokukata is another wrist release kata, but has yet another spirit to it – one I can’t really express yet.
I like trying to figure out these puzzles.