Why would Nintendo let that happen if they already have Mario Kart 8? I'm pretty sure they want Mario Kart 8 to sell as much and as long as it can(like Mario Kart Wii), so they wouldn't make a game that could even potentially damage the sells. Plus the Wii U isn't doing good enough to make a game that might not sell well anyway.
I could see them putting it on 3DS though. But, as part of recent Nintendo game hoaxes, it has to be on Wii U.
I could see them putting it on 3DS though. But, as part of recent Nintendo game hoaxes, it has to be on Wii U.