Yes, in my mind there are at least two levels of procedural generation:
1) Generating the layout of the world, placement of entities, and other world states (such as available quests or plot devices).
2) The generation of the actual content itself (NPCs, items, terrain, flora, fauna, etc).
Here, I'm mostly referring to the second type. :)
As far as the first type, there is a LOT more you can do with chaotic systems because they are often AI-driven, and AI-driven things can (potentially) have emergent results (although even an AI-less system, like Conway's game of life, can produce many interesting results).
1) Generating the layout of the world, placement of entities, and other world states (such as available quests or plot devices).
2) The generation of the actual content itself (NPCs, items, terrain, flora, fauna, etc).
Here, I'm mostly referring to the second type. :)
As far as the first type, there is a LOT more you can do with chaotic systems because they are often AI-driven, and AI-driven things can (potentially) have emergent results (although even an AI-less system, like Conway's game of life, can produce many interesting results).