I hate content carving. Just give us the whole damned game, no matter where we buy it, and no matter if we pre-order it or not. -_-
The whole game came out in Japan a year ago.
Some times developers add extra content for people who had to wait long, or for them to double dip.
Resident Evil 4 on PS2 for example had Ada Wong's story campaign, which wasn't present in the Gamecube version.