What BW2 might be is generation 5.5. Please hear me out. What keeps it from being gen 6 is the more numerous ties to the story of its predecessor (such as Kyurem). One of the atmospheric features of gsc's Kanto was the changes made, such as the veridian forest being cut down, and Cerulean cave being destroyed. These things were only missing in the original versions, and it was probably just for data space, but it created an air of sadness, that things aren't the same as you remember them, perhaps not for the better.
BW2 might try to do this in a similar way, with the Muskedeers being gone (among many landscape changes). Something would have to take their place, as otherwise the game would feel too empty. Jhoto had a new set of pokemon, along with a new region. So in the most extreme case, we'll see a set of brand new pokemon and a new region. At the very least (of this most extreme case) we'd see new legendaries, with Kyurem being the main focus (because gen 5 is trying to tell a story).
My rant is over, now you can call me stupid.