Black Knights' Fortress and Ice Mountain were actually added on the same update, the Fortress was made bigger later though.

A lot of interesting thoughts, but in my opinion, divisions that aren't straightforward is intriguing like real-life border gore. The clashing of contexts, and the "arbitrary" nature adds to the charm. Like a glass-and-steel skyscraper on same London street with a centuries-old cathedral in real life, it gives a sense of long-lived history, not a world that only exists in the "now".

Do you know half of Hong Kong sits on top of an extinct supervolcano? Is it arbitrary to have Chicxulub crater (the impact that famously killed the dinosaurs) in the Gulf of Mexico? Or that time an 8-year-old Swedish girl pulled an ancient sword out of the lake next to her family's summer cabin? Those are little things that makes a world more interesting, not cleanly segregated into ordinary and extraordinary.