I know during the “Lore” reason why The crown pavilion wont be open after the QJ is because the queen can’t fund it year round.
What about the Pact? They can use it as a sort of training grounds.
They can open it 1 week every 8 weeks, and seperate the zones to have mobs belonging to each Dragon (DSD and Moldremoth can be added later)
It can basically be content just like SAB, which can easily be opened again and again with new changes.
Even Dragon based bosses for the Gauntlet.