It would be like playing 1 game from every Pokemon generation, but once you beat your first region you leave your Pokemon behind (you can only use those pokemon in the first region at this point) and start with the next region's starter, then when you beat that region you can use all of your Pokemon in both regions, and so on. Basically, you start a new region with a new starter, and when you beat that region you can use any of your pokemon for side quests and after-story gameplay in THE REGIONS You HAVE BEATEN. That way it won't get tedious since each new region has a new story and you won't be destroying every route 1/29/101/201/Unova1 trainer when you start. And say when you get to Hoenn you unlock double battles, and new features as you go along regions.