For a long time I've been thinking about all the kind of stuff I'd like to do if I were in charge of making a Pokemon game and one of those things would be to make a huge postgame sidequest (a la Looker Quest) that revolves around Mew, Mewtwo, Faraway Island and Mr. Fuji.
Faraway Island would be a *huge* dungeon that you would first go to after agreeing to help Mr. Fuji attempt to collect Mew DNA. He'll take you there on a boat, but once you arrive, you're free to explore it as you wish, without all the dialogue interruption that plagues recent games. The island should be as large and complex as a Zelda dungeon (like Twilight Princess, not BOTW) with a deep and dense jungle theme and at the end you will find the Mew DNA that Fuji wants. Other rare items on the island would include Mewnium Z and Mewtwonite Y.
Once you deliver the DNA to Mr. Fuji a storyline that's basically The Birth of Mewtwo will begin. It's the best story to ever come out of Pokemon so I think it needs to be canon in the games.
