Come to think of it, when Lugia was first introduced, it was called, "Pokemon X".
Towards the end of Nintendo Direct, Iwata seemed to emphasize "some" when he said that we'd be seeing some of our old pokemon in 3D. I'm only speculating, but could this imply that perhaps not all older pokemon would be available, in a similar way to how Pokemon Ruby and Sapphire didn't have a feature to transfer pokemon from the 2nd gen games? Or perhaps this simply means that not all older pokemon are available to capture in Pokemon X and Pokemon Y, and we would have the option to transfer over any older ones we have. It's possible that our pokemon collections would be starting all over again, in the same way as they did when we played Pokemon Ruby and Sapphire. I wouldn't mind that too much. I'd probably welcome it, considering I have boxes full of shinies, legendaries, event pokemon, and competitively-trained pokemon that are getting to be a chore to transfer each time a new game is released.