I must admit I quite like the idea of bundle exclusivity for a short period of time. I.e. Mario kart bundle 2 weeks before the game is released separately.
I seriously hope the game is bundled as an optical disc and not a code. If they want to maximum sales bundle a second game like mario bros u make that a code but not mario kart. It devalues the bundle as Nintendo don't have a robust online service and the perceived value is far higher as an optical disc.
I've been playing a bit of Mario Kart wii at 1080p 60fps emulated on PC with Dolphin. Looks amazing just up rezzing that so a proper HD mario kart will be far better.