Do you think they will? Among the "old characters", they are the ones who appear at least once every region, even if just in fantasy form (I'm thinking about Hoenn, though they had a lot of Chronicles episodes back then). Do you think this trend will go on now in Unova? One may think that the answer is positive, due to the fact that Team Rocket as an organization is more important now, but we may also think that they won't appear because of the fact that their latest appearances had them as goofy as Jessie, James and Meowth, so it would be strange if they appeared (even if they could also have a reboot, as JJM did - though I believe it would be impossible for Jessie to ignore their rivalry).
What do you think?