@MarkL: #visuals and #non_visuals define whether a disease is available or not. You are thinking about #visuals_available, which also explains your question: there is no #non_visuals_available, at least not until the developers decide to add it, which I would approve of. =)
@L_konings: Now that's probably a matter of preference, but yea I could randomize it abit.
@Lego3: I agree, those are already on my list in the first post.
@Grimdoc: consider them done.
@alanwoolley: I don't mind adding it to the project, I don't know how though..
I'll probably release a new version tomorrow.