Title of your game?
Emergent systems are hard, I know, but such engine if done right once may be the base for many, many games. Developers may provide some declarative description of how world looks and behaves, press button and it lives. ;) Well, that's how I imagine it. I'm slowly writing prototype in Unity, as you have suggested.
You know Dwarf Fortress?
RE: How To Create Infinite Quest System for RPG Game?