The Wii U has been out for about half a year. Has ANY console actually had even a decent library at this point in their lifespan? Basically every console starts with a couple mediocre exclusives, one or two good exclusives, and a ton of ports. (And god forbid if they're bad ports.) It's usually only the fall following a console's launch that good games start coming in any appreciable number.
Nintendo has a pattern of overdelivering with the consoles, and then underdelivering with the games available for said console (at least at first).
EDIT: I should add that this is a relatively recent pattern; the N64 and the Game Boy Color are definitely stronger as platforms (with all their available games) than as consoles. Somewhere between the Game Boy Advance -> 3DS (which has terrible game availability for an awesome console) and the GameCube -> Wii, the pattern reversed itself.
The European launch (5? 6 months later) had those two, plus Star Wars: Shadows of the Empire.
Also, the ping pong game (and 100 pin bowling) in Wii Sports Resort is probably worth the money for the whole disc, which is another way to get the dongle.
they keep regurgitating the same franchises.
they almost did something new with n64/gamecube, but just because the 3d shift forced them to. (e.g. pikmin)
the DS almost pushed the envelope again, but they quickly settled to just regurgitating old franchises again with an extra map screen or something else that is irrelevant.
I think the problem is that the Nintendo platform differentiates itself on actually being different, and in this day that isn't exactly a selling point for game publishers, even if it is for the consumers.
Would you as a game designer/publisher rather build new game customized to the experience possible with the Wii or Wii-U, with their limited audience, or would you program to the lowest common denominator so you can ship on all consoles (keeping in mind that the more you customize for one, the harder it is to maintain the integrity of the experience of the game)?
But ultimately, i shouldn't care much about that. That's a market issue nintend surely foresaw when launching wii and wiiU. i'm just buying a console on the promises (by nintendo) that games will be fun and utilize the full potential (did they demo 12 clones of call of duty on their launch videos? because that's pretty much what's available). Nintendo should be doing a better job there. even if it's opening the devkit to everyone. They have failed me. ...is the wiiU a failure because of what? i wonder.