I don't get why people feel like they need another region though. It was just one single game. Everyone's fine with a new world map for Final Fantasy or Fire Emblem, let's just enjoy the new one and you can replay de past ones if you still have the game or whatever.
By the way, you may not notice now, but Pokémon was never an open-world game, and probably never will be. Oriental game design strive for a more goal oriented approach. You'll never get an equivalent to, idk, Skyrim "freedom" in Pokémon. Nor you'll get to really choose your own path, the game is set in progression, so stronger gym leaders will have stronger Pokémon that you can't possibly win yet. An open game would be just a design headache
By the way, you may not notice now, but Pokémon was never an open-world game, and probably never will be. Oriental game design strive for a more goal oriented approach. You'll never get an equivalent to, idk, Skyrim "freedom" in Pokémon. Nor you'll get to really choose your own path, the game is set in progression, so stronger gym leaders will have stronger Pokémon that you can't possibly win yet. An open game would be just a design headache