This might be more feasible-ish in a community effort? I'm not entirely sure how the jigsaw system (the subsystem the game uses for building villages and basti

This might be more feasible-ish in a community effort? I'm not entirely sure how the jigsaw system (the subsystem the game uses for building villages and bastions from a large palette of pre-builts using a set of rules and connectors) integrates with the custom world generator options, but that would seem the best bet for it in a vanilla game. The problem with an "official" player creations is both vetting them and the social backlash because you didn't pick little Timmy's shack. As well as the disjointedness of theme that could occur with a player's playstyle. I play a modpack. Create: Above & Beyond, they've added a bunch of new random structures to the game, but they're all within a similar theme of quasi-medieval for the surface structures, and a few of the underground ones stray a bit more modern.