I always thought the whole Dissidia concept would be interesting for character-driven plots and conflicts. I figured it might be worth a shot to make an RP out of, so here's the outline of what it might be (thoughts / display of interest always welcome):

- You play a character from the Final Fantasy series (offshoots like Bravely Default included).
- This takes place sometime after the original Dissidia series. You don't need to have knowledge of the past games to play.
- You have been recruited as a Crystal Warrior in an eternal conflict between the four elemental crystals (Fire, Water, Wind, and Earth). 
- Crystal factions of opposing elements are always at war with each other (Fire vs Water, Wind vs Earth).
- There may also be an outsider/antagonist faction that causes problems for all of the crystal factions.
- There will be a neutral territory for people to hang out in. Much like Dissidia, there will be places from the original FF games for characters to fight over.
- While the overall goal is securing territory and warring against opposing crystal factions, subplots are encouraged with GM cooperation.