Hmmmm... I think XV will have something to do with crystals, characters with unusual costumes that generally have way too many zippers, and one character that has a ridiculously huge sword. This character will be regarded as a badass, even if he is the biggest pansy since Cloud. Chances are there will be a character named Cid, who more than likely will have something to do with an airship.

The storyline will probably revolve around saving the world from an egotistical mastermind, a monster that destroys villages, an androgynous bishounen in a trenchcoat with mommy issues, an evil sorceress, etc. There will be moogles. There will be chocobos. There will be a few different love interests. Someone will probably die in the storyline.

As for specifics, I have no idea.