TBH, I don't really think there's any 'must have game' anymore. There's far too much variety and quality in the games industry for that one killer app to really boost the Wii U's sales. Its kind of sad to say, but its true. Steam has the most extensive games library right at your fingertips, sony and microsoft have pretty robust physical and digital offerings as well. Sure the Wii U may have some amazing games with more in the pipes, but I just don't see anything being amazing enough to 'change its fate'.
The biggest potential system seller that Nintendo has in the works right now is Zelda, but lets look at Skyward swords sales for a moment. 3.88m lifetime with 101m Wii's sold. Meaning somewhere around 3.5% of Wii owners bought the last console Zelda title. Lets apply those numbers to the Wii U. 10m Wii U's sold(rounded up for simplicity) means 350,000 copies of Zelda U, but lets be super optimistic and say that 350,000 current Wii U owners will buy it, and another 1.15million people will buy a Wii U just for Zelda. Then lets take into consideration that Nintendo will probably sell about 3million Wii U's this year and add 1.15 for 4.15million. Assume a 6 year(generous) console generation and for some reason no drop in console sales for a steady 4.15m for the next 4 years and that puts the Wii U's lifetime sales at right around 26million units sold.
Sure some other games will come along that will move some extra units, but lets be honest here. The killer app just doesn't exist in the gaming world any more. Oh how I long for the days when Genesis did what Nintendont.
“What I say is, a town isn't a town without a bookstore. It may call itself a town, but unless it's got a bookstore it knows it's not fooling a soul.” - Neil Gaiman
