» those thousand words ♥
It'll still be a ton of work to include a new region, even with the planning. I highly doubt that any other region other than the one we're getting would be implemented not just because of the graphics, but because of the mechanics, too. You're revamping the old region and fitting them within current generation mechanics. I don't think it's something that would pan out too well.
Granted, it could be argued that they did this with HG/SS, but hardly a thing was changed in HG/SS, other than the follow me, upgraded graphics, and the Pokeathlon, I doubt there was much that was significantly changed. With these games, however, I would imagine it's like Unova in the fact that it's a completely new start, which means there wouldn't be any ties towards any other regions whatsoever. D: