Personally i would've thought this games main objective would be:

SPOILER!!:
Getting Fang and Vanille back from being crystallised, and it would also inlcude Serah as a playable character?


I will probably buy this game although i didn't enjoy the lack of towns in the original XIII, Who is this mysterious dark haired gent in the trailer?

Also i saw someone wanted to see a HD version of the trailer:YouTube - Final Fantasy XIII-2 Teaser Trailer [HD]