I've been thinking along the same lines as well. The beginning doesn't feel much like a post-apocalyptic wasteland, a lot of these quests would feel more at home in a generic high fantasy setting.

What's especially weird are the countless noble estates that pop up around the world, waiting for someone to be escorted there, at which point they promptly disappear in a puff of smoke. Landmarks in general shouldn't just appear and disappear based on your quests, unless they're truly unremarkable places except for your business there. It's okay if a random cave with wolves in it disappears when you are done with it, but a surviving noble's estate should be a big deal that matters beyond a single escort quest.

Yup. I would think the devs considered this already. Hopefully it's something that could still be worked on.

Well, unless estates are an integral part of the game mechanics I don't see a problem of them disappearing in the map. It's left to our imagination to assume that that estate still exists within the Realm but doesn't present problems that need attention from the player. However, a certain estate could re-emerge in a new quest, requiring more assistance.

Maybe having them there but not being able to use them would be distracting for the player and even frustrating for some. There could be some more important landmarks visible and then have them restored to their former glory. Other places-of-questing could just randomly appear according to a 'make sense' approach and civilizational development.