This is just a thought provoking exercise, not a necessity for the game. However, if added somehow in the future, it would be really cool.

1-Music selection=I was just wondering how cool it be to select in the menu what kind of battle soundtrack you'd like from previous ff games, and even ff games that come later. This way you battle a boss with, let's say, a boss theme from ff8, or ff11, etc.

2-Re-run Dungeon=Sometimes in DF we find a random awesome party, wouldn't it be cool if by the end of the dungeon we could all checkmark on "Restart"? The instance resets and we all go at it again without having to queue again.

3-True customization of gear/weapons/etc=Instead of having already presets of gear to make, why not give an option to crafters to manufacture their own designs? Not just the shape of the armor or weapon, but the logos you can stick in them, and colors? It would give every player a unique look.