I agree in principle with what you're saying except that learning to walk is a bad analogy. Walking is an instinct -- something that's programmed to happen by our genes. All humans walk on two legs, but not all humans study Aikido. Aikido may be composed of natural movements, but it is not composed of instictual movements.
I like your breakdown of how the average person learns. I think that I tend to learn a bit better from hearing something than the average person, but that breakdown looks like a good guideline.
P.S. How many "average" people take Aikido? I thought that all aikidoka are above average.