As published on campustechnology.com and an interesting in-details LMS comparison document "A Comparison of Learning Management System Accessibility"
Although it is referring to a Moodle 2.3 version, I guess there is some interesting points we can dig out and Improve Moodle some more
In reading the results reported in the html page, essentially there is only a comparison of each tool's abilities in accessibility. The report says nothing much, each tool has some strengths and some weaknesses in this area. Basically, the comments could be used by devs and Moodle.org to point the accessibility options in a particular direction, culminating in a better product for the disabled.
Generally, accessibility has always been an issue in all software, and there is a huge risk that developers of any product will eventually try to create a "system of perfection". This is a dangerous option, as it concentrates efforts and resources into a particular mode and can leave other areas of development in that no-man's land of under-resourced. While studies like this are valuable, they must be treated carefully, with respect and due diligence, but not with an overwhelming sense of "doing something to fix a problem". True accessibility, that is being all things to all people is not achievable I suspect, so as Moodle evolves, so should the accessibility options. They will get better, but it will take time.
The origin of this document, 2013 I understand, is already behind the improvements made to each of the products mentioned. Is there any update to this study?
Indeed, an old report. and much have been done since. but still, new code bring about new issues.
Here is a list of open issues on the tracker: