For a game like this, development costs pale in comparison to marketing costs. So whatever platform it does end up on, expect a $30,000,000-40,000,000 marketing campaign.
Now one of the ways in which platform holders "money-hat" games is cross licencing deals and as Microsoft is more willing than most to get out their wallet to spend money on marketing, and what they have spent has proved itself effective in a lot of games such as Bioshock, Gears, Fable 2 etc.
The userbases of the PS/360 combination have proved time and again they will eat up big games like this in multi-million numbers on both systems. Also the game features characters which appear in FF and SE can assume most of their FF fanbase is on either system anyway and Disney doesn't care where it goes so long as they get their money.
So whether its exclusive, timed exclusive or whatever I say its greatest chance is to be on one of the HD systems.
Tease.
