Quoted By:
In my head I've been playing with the idea of like a primeval region.
Perhaps the player travels back in time, like PLA but older, perhaps is just primitive. Where you're dealing with the direct ancestors in a real-ish evolutionary sense, of modern pokemon.
Where you see like a Bug/Water Kabutops that is a clear ancestor of Scyther (based on a headcanon that the shared scythes in the designs showing that they're related).
Or some amphibious shark monster that is the shared common ancestor between Garchomp and Sharpedo.
Stuff like that.
The region and all the buildings and tech in it would look deliberately primitive. You as the player could even see it grow. Where map tiles get switched out after boss battles in a way that makes it seem like the region is expanding or whatever.