I think that Nintendo made a mistake by not introducing, or really trying to change up, some IPs. If the stats are correct and the average age of a gamer is somewhere in his thirties, that means that he or she has been exposed to Mario, Zelda, and the gang's games for almost thirty years. There's a good chance that fatigue has set in with these franchises for many people. I just don't see how releasing another Mario Kart game will get people to buy the console.
When it comes to Zelda or Metroid, I think Nintendo REALLY needs to shake things up. Die hard fans don't want change but I think they have to change in order to sell consoles. Like it or not, an open world Skyrim like Zelda would get non Wii U/ Nintendo fans talking. Same thing for Metroid. The problem, of course for me, with these games is that you know 50% of what to expect before you start the game. They need to surprise us again. That's what OoT and Prime did.
Nintendo also destroyed the Wii name. They let the Wii die on the vine for over two years releasing no games and providing nothing new. Gamers and casuals realized this. I remember when I was a kid going to Toys R Us and seeing the wall of Nintendo games. Just rows and rows of games with little slips to take to the cage. Every time I went, there seemed to be something new to see. Fast forward to kids with Wiis. Your mom takes you to the store and you run to the game isle to see what new games have come out. Hmmm, nothing new. A month later, you check again....nothing new. Meanwhile, the ps3 and 360 sections are the ones with rows and rows of new games. "Mom....can I have an xbox?!!"
