Now that I think of it, every FF I have played follows one of two storylines.

1. Salvage the crystals and defeat a great evil.
2. Rebel against the empire.

FF 15 should get something more creative. For example, I like how in DQ 7, there is only one island, and you have to find all the rest. And in Tales of Legendia, the whole island is actually a big ship. FF needs a story that is creative and completely off the wall like the two examples mentioned. I'm tired of crystals and empires.

Of course, I have never played 8-11, but I imagine they follow one of the two patterns at least somewhat.