While it can be done technically with the existing methods to place modular POIs, that then form a random variation, I dont like this kind of hacking around something that should be done internally by the game.
Its way easier to realize such a system within the games code itself, and then offer users to create custom POI-parts and maybe define some generation rules (eg what should fit to what).
On the other hand, such a system would be more needed if there where only a handful of POIs. But the game has quite an extensive amount of handcrafted POIs already. More so than most casual players would ever clear out.
So procedural POIs are probably not seen as a priority.