There is no win condition for you. A new developer would ultimately be tasked with making the game how Game Freak would make it, with the added nuisance of having Nintendo be constantly looking over their shoulders, to ensure the games produced would do what Game Freak's have done for the last 24 years and continue printing money with the franchise. It's either stick with Game Freak, who have the edge in creature design for their world, or move to another studio, who may have better coding skillz, but who'll ultimately end up as nothing more than Nintendo's bitch, akin to how TPC treats its pet development studios.
From Nintendo's point of view, continuing the status quo is the most sensible endeavour, Game Freak don't need the overwatch, they're guaranteed to release a game that sells millions of SW units and everyone makes guaranteed bank off kids, like they've done since this whole thing blew up.
