To help out colour blind people, how about adding some filters in for the common kinds of color blindness so you can see what your game would look like for people with that issue? It would (a) help people make games more accessible, and (b) I think having a tool that helps people make games easily for people with challenges would make a great selling point for the engine.
I'm not sure what other accessibility features the engine could address, but there might be others like support for people that can only press one button or similar (I'm envisaging a "game for one button" code module possibly - though I'm not sure how much common functionality there would be for a standard module).
What about the ability to slow the whole engine down for people with slower reaction times?
Mouse/joystick acceleration options?
If we can expand the technology and output games to encompass other user groups who may have certain impairments would be a good move and we are all for that 
