I think this would be really cool, and I feel like it wouldn’t be nearly as difficult to make it work as it may seem. Assuming the game is planning to cap off around Rank 10 (or at least, bring our current world map to a close at Rank 10), it doesn’t look like it would be too difficult to manage.
Story-wise, they could have a cataclysm of some sort hit Orsha, and then have the main quest line involve trying to take back the city, as it were. I would probably focus Rank 9 around that story event and tie up the Grand Forest area, then have Rank 10 finish up the Royal Territory and open up the Star Lit Lake.
All they would have to do is leave the old maps and kill counts in the adventure journal as a mark of honour for people who cleared it before the update, then add new copies for the revamped maps. Redoing new sets of quests and spawns would be no more work than producing new maps from scratch, and it would put a lot of the resources that are currently being wasted on basically unused maps back into use. With the combat rebalance patch, you don’t even need the Klaipeda side of maps to level anymore, let alone the Orsha side, so its not like there would be a terrible loss in that respect lol.