When did pokemon become a game where people cared so much about the plot. I can assure you whatever the plot is, it will hardly be groundbreaking. I've never really played the games for the story; I mostly care about playing through and training different pokemon each time, getting a feel for as many species as I can. The plot's going to be a rehash of the same plot we've had every game before, with a different evil team trying to accomplish a slightly different goal.
I think people got caught up in the fact that BW had some semblance of plot to think that that is what these games are built on, and not the pokemon themselves.