"being able to figure out wikitext" might be a good attribute, but making it a requirement pretty much sacrifices any hope we have of getting rid of our systemic bias....
Individual editors' skill with wikitext should be independent of almost all of the systemic biases from which we suffer except perhaps math articles with sections ordered by utility to the typical reader. The effect, if it exists, should be stronger on the Simple English Wikipedia.
I'm not opposed to further improvements and measurements of the Visual Editor, but I am opposed to the absence of honest cost-benefit evaluations of supplemental opportunities for increasing participation.