I think a lot of people are sitting by and waiting for Mario Kart 8 to release next month before they invest in the Wii U. Mario Kart Wii was the biggest selling game on the system (not including Wii Sports), selling over 35 MILLION copies. Lots of people love Mario Kart and will pick up a Wii U for that game alone.
That being said, Mario Kart 8 is a band aid for a much bigger problem. There is simply no software coming out this year that anyone is discussing other than Mario Kart, Smash Bros, Bayonetta 2, X and Watch Dogs. There's apparently over 100 downloadable games in development for Wii U, but indie games don't sell systems, AAA titles do. They need to put the 3DS on autopilot and focus on getting games out for the Wii U. They have billions of dollars in the bank, so I have no idea why they passed on acquiring Atlus.
Nintendo refuses to acknowledge there are gamers out there who want to play stuff like Bioshock, Fallout, Borderlands, Mass Effect, Dead Space and Dead Rising. At this point, buying a Wii U is like buying a Blu-ray player that only reads Disney blu-rays. Most of Nintendo's audience has been with them for several generations -- they're adults and want new, more mature experiences to go along with the nostalgia trifecta of Mario, Zelda and Metroid.
Where are the new IPs? As much as we love these franchises, they're starting to get a bit stale. It's time for something new. There is so much potential with the gamepad that is being overlooked. Imagine how AMAZING a new Fatal Frame title would be on Wii U, when you actually have to hold up and use the gamepad to photograph the ghosts! But Nintendo is stubborn and continues to think that cranking out incremental updates to Mario, Zelda, Animal Crossing and Wii Sports is going to sell systems. It's not. While that might be enough for Nintendo fanboys, it's not enough for the modern gamer.