This would lead to very predictable results in the absence of a world and geology to consider; as the current algorithm would tend to find the same optima each time. Even with the architecture changing path lengths, room shapes and sizes, and preferred verticality, it would still find fundamentally similar solutions. On the one hand, merely introducing a map will provide a lot, at least near the surface and around the caves, providing hard constraints on where you can build will squeeze and push the fort into different shapes.. but I feel there is another element needed.
▲ Ah, no, I think this is what was missing from my thoughts on connectivity. The initial plan might always be the same, because there are only so many way a small number of people will choose to live together, or set up a fixed size fort optimally. The food, dining and sleeping areas are linked in some way.... but as the fortress grows, as needs change, and requirements change, the planned areas and their locations may be insufficient, leading to new and interesting structures. No need to mess about with complex math to generate interesting structures, when events happening over time can do a lot of heavy lifting for you.