Well it was speculated that with the sighting of movie Arceus you'll activate the lv. 1 Dialga, Palkia, or Giratina, so we'll see if this is true later on. However, on talk about the three bird, I doubt they'll appear seeing as they were available in Platinum. Mewtwo however could have a slight chance, but we'll need further information on that later on. I'm speculating that since this game is probably not a full featured DSi-only game, they may still continue the GBA slot feature to access other generation Pokémon like in DPPt [I'm not sure, but just maybe]. It is possible and can happen, and then they'll make the next generation game either DSi-only capable or made for a new system overall.
Though, the best news so far for me is getting to see more pictures of Johto. There is speculatiosn of whether or not Cianwood now has a canal or if it is part of a new location they've added into the game. It is also being rumored by some that a new Elite may be added in from one of these new locations, but isn't sure as the pictures are still kind of unclear. So far so good though, and I'm expecting in later scans we'll end up getting insight on gyms, and hopefully the story of the game next month most likely.
EDIT: The location of Arceus seems like no where ever seen before in Johto, so I'm wondering if they brought back a kind of similar area closely related to that of the Distortion World [/?].
