Iwata is a f**king clown. Wii U pulled in 481k in the US, and all the only driving forces behind that was a bundle with a year old game and SM3DW. All the guy had to do was make sure Mario Kart and Donkey Kong were ready for the holiday season and the Wii U most likely would have outsold the PS4 and Xbone. The guy runs a company that has more valuable and great selling properties then any other gaming company on the planet by far, and has found a way to royally screw it up.
That's not "all the guy had to do". Gaming is more then just pressing a button and making a game pop out when you want it to. Mario Kart probably wasn't even done.
That year old game is the sequel to one of the top selling games of the previous generation. SM3DW is the sequel to one of the top seling 3DS games. It's doubtful Mario Kart and Donkey Kong would have made much of a difference, Donkey Kong especially, given that its prequel didn't hold a candle to NSMBWii's sales and NSMBu failed to move Wii U very well at all.
This is about more then software now. It's about the Wii U itself. Whether it's the price, the lack of features, or simply the changes in the marketplace over the last three years, the titles Nintendo provided SHOULD have been more then enough to jumpstart the Wii U's sales. Barring a change in other variables for the better, MK8 and DKRTF won't help much, and rushing them out for a holiday release would have only left 2014 completely barren, which was a major issue in the first half of 2013. Any sales that Nintendo could've made in 2013 with those titles they'll probably make in 2014.