Adaptive plot.

I want a Final Fantasy - or even Bravely Default - where there are four fiends wreaking havoc on the four crystals, but it's more open-world and you can go to any of the four realms first. And whichever one you fight first is at level 10. Whichever one you fight second is at level 30. Then 60, then 99. But not only does the difficulty scale, the plot adjusts accordingly, where after you beat the first fiend, the three other fiends get together and...I don't know, do something to try to come after you. There could be optional triggered ambushes/assaults/battles based on where you go and when.