Since you have the basics, you can go in any direction. Almost infinite possibilites. Play rpgs of different kinds and see what you like or not. If you want to stick to gambler kind of gameplay, why not go deeper in that? Casinos have chips, roulettes, cards, magicians and drinks. How about mixing those things with the classical medieval style in some way? Like the player is in some futuristic casino where influence and gamble on the life of heroes from the past. I'm just rambling nonsense here though.
I'm sure that if you ask the question the right way in the /agdg/ thread, you will be swarmed by people chipping in with interesting ideas that will spark your imagination.