Here is an interesting extracts on the development of Final Fantasy Versus XIII from the Japanese Square Enix Twitter page for you (thanks to Final Fantasy-XIII.net for a translation).

What percentage of Versus is done?
Nomura: Things are not connected yet, every part is moving along separately. However, we have gotten airships working over the world map.

Now I can't remember if the airship thing was revealed ages ago (so please forgive me if it has), but I am really excited about that and glad it is making a return to the Final Fantasy series (if it is the free roaming style from Final Fantasy IX and earlier).