I believe what the OP is suggesting is an entirely different sort of terrain. It’d be an entirely unique offering from PS, but I like it so I’ll jump in to try to take up his case.
What he’s referring to isn’t 3D terrain that sits on the table horizontally, but rather stylized 3D renderings that stand vertically and give the impression of depth. So instead of printing a bunch of streets and buildings, you’d have 3D tiles that print flat, but stand vertically like a theater backdrop. It’s the same idea as a matte painting, but updated to be printable. One could be the backwall of a tavern, one could be a country lane, one could be a medieval corridor, etc.
I honestly think this idea is fantastic. There are so many use cases for this, even from a super primitive thing like cave walls. Instead of printing for 30+ hours to get enough cave walls that stack 6-8″ in height to create a backdrop, you could just print two cave backdrop mattes that provide the sense of depth.