Nintendo would never do that, simply becasue:
1. Adding all the regions would allow you to catch all pokemon, thus defeating the purpose of buying the two versions (yes, the versions are for that, not for some story purposes).
2. It would take too much time to develop.
1. Adding all the regions would allow you to catch all pokemon, thus defeating the purpose of buying the two versions (yes, the versions are for that, not for some story purposes).
2. It would take too much time to develop.