Yep, right here, had a heads up from Sik!
Agree with the above posts, audio only games aren't the best approach to take. Instead, just make a regular game that is also accessible to people who are blind. It avoids you being restricted to a niche, means making a game that's accessible to more people rather than less people, and believe it or not visuals can sometimes actually be helpful to people who are blind.. most people who are legally blind do still have a very small amount of vision left.
And to give an example from another area of accessibility, if you broke a couple of fingers, would you then want to play a small selection of games designed specifically for people with less than 10 fingers? Or would you want to play exactly the same games as everyone else, but be able to rearrange the buttons so the most important things were in positions yoi could reach easily?
As far as preferences (assume you mean tastes?) in games go, that's a bit like asking what tastes people who aren't blind have. Answer: depends on the individual person.
One thing for definite though is to avoid the first ideas you have, they are likely to be the same ideas everyone else has already had... There are a million and one audio games already out where you're trapped in a maze, lost your sight, and have to find your way out.
Something that there's a real lack of is online games that blind and sighted people can play together. For this reason diceworld on iOS is very popular, as it gives a rare opportunity for blind people to play remotely with sighted friends and relatives.
What platform are you targeting? The easiest way to do blind gamedev is on iOS, every iPhone and iPad has a built in feature (voiceover) that assists how gestures work and speaks out the label of any object under your finger, so blind players can effectively 'see' the layout of the screen.
So if you're making a game that isn't reliant on timing and is about navigating an interface rather than a 3D environment, it can be really easy to make the game blind accessible.
The only catch is that it can only recognise UIKit elements, so you have to develop natively rather than use a game engine (although I think the sparrow game engine may support it, you'll have to contact them to check though).
So a good approach for coming up with an idea might be be to have a play around with voiceover, and think back through all of the game ideas you no doubt have knocking around that would be fun for all players, and see if any of those ideas would work with voiceover.
Then for blind gamers, there are three main communities: the Applevis.com forums, the audyssey mailing list, and the audiogames.net forum. Through all of those places you'll be able to find lots of puerile happy to be interviewed, suggest game ideas, help with testing etc. Applevis also has listings of hundreds of iOS games that are already build accessible.
This GDC talk might be helpful for you:
http://www.gdcvault.com/play/1020415/Beyond-Graphics-Reaching-the-Visually