I want so badly for dwarf fortress to just be an API to the simulator and let the community build the user interface and view layer. That would make my life complete. And also completely unproductive.

That only solves half the problem, though. There's still the issue that it's a single-threaded game which allocates and accesses memory randomly on the heap. So there will always be a limit on how large and complex the game world can be.

What I'm still waiting for is the game that comes after Dwarf Fortress, the game which is appropriately engineered for performance and is thereby able to be even more ambitious. We've seen a ton of less ambitious DF clones, but nothing on the other end so far.

I have to think that anything more ambitious than DF would either take a crazy genius with lots of free time or a large team. Possibly both.