My understanding is pace partners have changed routes a couple of times, but these were “one-offs” either due to a bug or because Zwift was testing things.
To try new things, I think they should add pace partners to other worlds. This way they could add partners with different names on different types of route for several weeks, without harming opinions of the “regular” pace partners.
I can imagine some people preferring to ride with Cara Cadence in Watopia, while others enjoy the odd change to ride with “her brother Colin” in Yorkshire, or Cleo in France, etc.
And @Matt_Pyke_SJBC That’s just your route choices - you choose which route to ride when you enter Zwift but you can change onto other routes when you come to junctions. The pace partners stay on their set routes whatever you do.