These are games that you wish Nintendo will launch. Considering how previous threads went I will not ask you to be realistic.
My ideas:
Captain Toad: Treasure Maker. Like Mario Maker, it allows you to create and share your own threads.
Mario 3D Maker. Same idea, but might be a lot more complex to make.
Super Mario Theatre. For Wii U. A lot like a dream cross between Galaxy and SM3DW, but the bottom screen always shows a band/orchestra of toads, koopas, etc that actually play the song (and with as accurate movement as possible). These players would be very animated, keeping the same emotion as the music. Additionally, you can manipulate the band/orchestra to alter the world (such as tapping on the secret item special effect player would wake him up and him playing would reveal the special item.
Paper Mario: Pop-up Star. This would try to make Paper Mario as photorealistic as possible, as if you're watching a high-speed stop-motion production of TTYD. No low quality psudocardboard like LittleBigPlanet though; The Mushroom Kingdom deserves high gloss cardstock. Maybe the occasional paper joke but please don't go overboard ("You can't defeat me... I'm laminated!")
