Whilst I'm not a fan of pretty much any of the zones you mentioned, I can see what you're shooting at and I have to agree that these kinds of things would really make the game world feel special, with explorable open world dungeons to venture into and find treasures etc.

My fondest memories of FFXI involve the beginning of the ToAU expansion where everyone ventured out into the new world for the first time to see all the amazing new areas and complete the new storylines. What they didn't do is sit in cities with a content finder immediately, and never leave because you get teleported inside the dungeon. (Disclaimer: I recognise that people gathered in cities and shouted for group members, but there was always some degree of travelling and rarely were you shut off from the rest of the playerbase like a 'theme-park' style of game with dungeons).