Topic moved to General Gaming, not specific to Nintendo.
Such a game you suggest would (a) require continual patches for new charas/cars, (b) be unwieldy in terms of data size unless a cloud storage was established, and (c) isn't stimulating enough for a majority of gamers who dislike racing games.
I think one of the genres that could be made are those that combine puzzle (which is itself a very specialised niche, and not overly 'popular' in mainstream from what I gather) and a more popular genre like RPG, RTS or even a platformer, but the main thing that I would emphasize is the puzzle side's importance/major role rather than the RPG/RTS/platformer side.
In terms of a storyline, using a puzzle main genre leads itself to excuse plots, unless there was some crazy plot about how a terrorist organisation was using puzzles to brainwash citizens of the world, and a team of resistance "fighters" (like they fight >.>) have to break through such puzzles to stop the ambitions of the terror group. Maybe to appeal to more people, some of the 'puzzles' could be quick reaction events where characters' lives are on the line (bomb diffusion, operations a-la Trauma Center, etc etc)
IDK it's an odd premise, but it'd have potential if the storywriters make it convincing, and the game development team are creative enough.