[Suggest] Open World Dungeon Idea
This is really a simple concept that tells the story between a normal dungeon and how they go to the hard mode state.
Toss in some dailies, FATEs, hunt NM, sightseeing, and rare spoils to make it meaningful content instead of just fluff.
Now take Halatali. Ul'dah staff has to turn it from dungeon to training ground. That requires capturing the animals, building traps, and repairing structure. I'm sure there is a few hold over monsters from the old dungeon that needs to be cleared as well.
Edit: You could also use this to add light party based content such as group dailies.