During the first few kyu tests (6th, 5th and 4th) it is my opinion the students are learning the "alphabet" of aikido and its expectations, much as a toddler learns to talk. 3rd, 2nd and 1st Kyu are where they are learning to put understandable sentences together.....Dan rankings should be able to put comprehensive ideas and concepts together and communicate them via technique.. IMHO.
I like this analogy. But I would ask is the rank of shodan really worthy of comprehensive ideas and concepts? At this stage one is certainly better off then when he/she started but the ability, understanding and skill is still in a very rudimentary stage isn't it?