I think all developer should think of accessibility when developing a plugin, module or component. Wouldn't you like everyone to listen to your music including people with disability?
This plugin could be improved by adding tooltips or title tag when mouse hover the "play" or "stop", something as simple as that can help the accessibility community. Accessibility is the part which we tend to ignore or not aware but we should, hence I give this plugin an average rating.
I also think this is BIG missing gap in the audio player market in Joomla.
Ohh by the way, this extension is easy to install in 2 modes, manual or automatic, either way, it works just fine for me and the extension is fully documented, great stuff. Keep up the good work!