Brawl will almost definitely include an update for NTSC-J consoles. If this update is run on an NTSC-U console or a PAL console it will more than likely brick it (for NTSC-U consoles it's far less likely to brick than a PAL). There are workarounds, patchers that will remove the update from the disc and make it still playable. These don't always work, but with the extreme demand for brawl if none of them do the homebrew scene will get a workaround out pretty fast.
also http://www.youtube.com/profile_videos?user=queensaki&p=r
videos of the japanese brawl demo that they just got
Dedede is much more powerful than I would've thought