Some kind of procedurally generated fantasy world, designed around generating stories.
this sounds really cool. some of my favorite games are essentially sandboxes (mount & blade, pirates), and I like the idea of taking the sandbox and building in non-trivial, non-artificial non-deterministic stories.
When I see the same thing, I think a lot of better stories can emerge - a lifetime bond between comrades, a romance between a prisoner and the nurse who comes to heal him, rivalries between factions, a 500 year old cyborg who questions her humanity. So many stories can emerge.