The Wii IMO taught Nintendo all sorts of poor lessons on how to build a console. No need to have third parties and really a well rounded software library with diversity because you can just rely on Mario + party games ... which is fine, until it stops working. I mean sh*t they didn't even need to market the Wii after a certain point, the word of mouth was selling it by itself.
Nintendo got used to taking short cuts to success.
Well technically Wii U does have a pretty diverse if u include 3rd parties and some of Nintendos smaller titles
ZombiU+Walking Dead+Resident Evil Revelations-Survival Horror
Call of Duty Black Ops 2+Ghosts-Military FPS
NSMBU+Luigi U+Sonic+3D World+Rayman-Platformers
Wind Waker HD+Monster Hunter+Darksiders-Action RPG
Need For Speed+Sonic Racing-Racing
Nintendo Land+Game & Wario+Wii Party-Minigame Compilation
Tekken Tag Tournament+Injustice-Fighting
Assassins Creed 3/4+Batman Arkham+Lego City-Open World Action
Just Dance+Zumba+Wii Fit-Dance/Fitness
When the herd loses its way, the shepard must kill the bull that leads them astray.