I've heard that they actually will at least visit you over the course of the story (but are leaving later?).
"Home Base:
• Geralt gets his own motherfucking vineyard.
• It’s called Corvo Bianco.
• You can renovate it with large sums of money, the option I saw was for 5000 Orens.
• You can add a greenhouse of sorts where you can grow herbs for all your witcher potion needs, an armourer’s table, a stable for Roach (with its own stat bonuses), upgrade your bed, renovated interior and exterior, secret lab, guest room.
• Guest room where old friends will come to stay. They said the names Triss and Yennefer, but were reluctant to reveal the names of anyone else who might visit.
• Scaffolding and workers will appear after you choose to build something. Each change takes a certain amount of in-game time to complete, but you can just meditate til everything’s done.
• Can display your armour, weapons, paintings and books.
• Some paintings can be bought, or specially made, others are obtained through quests."
http://wccftech.com/the-witcher-iii-blood-wine-showcased-ten-gorgeous-screenshots/
The immediate surroundings of Novigrad and especially the area that comes with Hearts of Stone to the East of Novigrad is already pretty bright, tranquil and quite beautiful, don't you think? I thought the place where the big wedding happened was gorgeous.
Yeah, I wonder what this "Kovir" is like that they always mention in the game. Must be some beautiful and peaceful place. If they added a new expansion with a new country each year that would be amazing! They could totally do that...but apparently they have other plans.