Pokemon game idea

Following gen 2, given that it featured Kanto alongside Johto, it was somewhat hoped or assumed that the Pokémon world would just keep growing in the games, rather than restraining each game to one region. At least that was how it appeared to kids at the time.

One of the key reasons I resented gen 3 at the time was that it limited you to one region (I am not a Hoenn fan anyway) and it cut you off from trading and connecting with the rest of the franchise at the time.

Making a Pokémon game featuring all regions seems like an obvious idea, but given that Game Freak struggle to put out single region games to a high quality, multi-region games might be beyond them. I wouldn't put it past them to make Kanto DLC if we ever return to Johto or get a gen 2 remake.

That said, it might be possible in something like an MMO where the developers can build up and add regions over a long period of time, and the game is expected to last for years rather than a single release. I don't think Game Freak would be the company to make an MMO, though, judging by the online performance of their other games.