We know that the mind/body builds what for convenience we call "muscle memory" based on repetition.
To my mind building "muscle memory" is what we do only in the very first beginning of practice. Maybe the first one or maybe two years. I think, it is only needed to be able to reproduce the external picture of kata to a certain degree.
But after that I think practice should be about feeling inside to connect the body of tori internally. And also about feeling outwardly to connect the body to aite.
So it is my experience that the image of building "muscle memory" is limited to the very beginning of practice.
Yet the common "L-R-L-R, then switch roles" does not really provide repetition regardless of how many times one goes through the sequence.
Why do you think this pattern does not provide repetition?
Besides that: I'm not a neurologist but whenever I had to learn something by repetion, be dancing, calligraphy, piano, singing , ... whatever ... the teachers told me that my body or brain actually was learning during the pauses. Not while repeating.