I feel like that was mentioned as well at some point, but I cant remember where. Although I really don't think letting chocobos into the old dungeons is a great idea. They can't exactly handle gimmick fights. Imagine fighting the blob in copperbell with chocobos. "Opps, there goes the bomb." "There goes another one." "And another."

That said, I would LOVE to see a chocobo dungeon, that gives lots of chocobo exp, some exclusive barding, and maybe some other cool chocobo themed stuff. Have it be a 4 person 8 man dungeon, where while in the dungeon, everyones chocobo is automatically summoned. Maybe have bins of gysahl greens throughout the dungeon that can be interacted with to re-summon your chocobo if it falls in battle?

Could even go the extra mile, and have it be a reference to the chocobo dungeon games, and have a randomly generated layout everytime.