Here's a list of available and upcoming Wii U 3rd party games (most DL only games excluded, games not made but funded by Nintendo included):
ZombiU, Lego City Undercover, Monster Hunter Tri, Sonic & Sega All-Stars Racing Transformed, Call of Duty: Black Ops II, Scribblenauts: Unlimited; Assassin's Creed III, Batman: Arkham City, Skylanders Giants, Disney Epic Mickey 2: The Power of Two, ESPN: Sports Connection, Darksiders II, Tekken Tag Tournament 2, Mass Effect 3, Marvel Avengers: Battle for Earth, Disney Infinity, Warriors Orochi 3 Hyper 2012, Need for Speed: Most Wanted, Transformers: Prime, James Bond 007: Legends, Just Dance 4, Tank! Tank! Tank!, Ninja Gaiden 3, Your Shape: Fitness Evolved, The Walking Dead: Survival Instinct, NBA 2K13, The Amazing Spider-Man, Scribblenauts Unmasked: A DC Comics Adventure, Zumba Fitness: World Party, Skylanders SWAP Force, Just Dance 2014, The LEGO Movie Videogame, Adventure Time: Explore the Dungeon Because I Don't Know!, Castle of Illusion Starring Mickey Mouse, Disney's DuckTales Remastered, Lego Marvel Super Heroes, Young Justice: Legacy, Toki Tori 2, Trine 2, Injustice: Gods Among Us, Resident Evil: Revelations, Batman: Arkham Origins, Project CARS, The Wonderful 101, Bayonetta 2, Tom Clancy's Splinter Cell: Blacklist, Deus Ex: Human Revolution, Watch Dogs, Rayman Legends, Call of Duty: Ghosts, Assassin's Creed IV: Black Flag, Sonic Lost World.
Now add all those good to excellent available and upcoming Nintendo games to that list and you have your answer: Even if it ends up in third place, even if it will sell only 20 million units, the system is not in trouble.