KQED recently ran a report that reveals how aspects of gaming that we take for granted, like audio cues or keyboard controls, can be real obstacles for disabled gamers. Sure, it might lose a bit of credibility for finding fault with the many-buttoned controllers of "Sony's Xbox 360" and "Microsoft's Playstation 3," but it's an interesting look at an aspect of game design that doesn't get a whole lot of attention, just the same.
[Edit: Hmmm...sometimes the video works, and sometimes it doesn't. If the link above is being wonky, you can watch the report here instead.]