I don't think the system is a failure but it will probably take 3 years to get a semi decent library of games on it. After 3 years if it has nothing then we can call it a failure also if it misses most of the big releases, or if they come out with significantly reduced features. The 3DS took a ton of time to get the game library up to speed but this year is going to be epic and the system is selling well.
Well, this summer the 3DS will be 2 years old, so I expect it will be a year or two before the Wii U has a library that will stand on its own.
Gee, haven't we been saying to wait a couple of years to judge a console?