I think you must wait until Mario, and SSB for too many conclusions to be made. If they do well enough and I think it will, I think wii-u can and will essentially be the gamecube 2 (except that its weaker than it's competitors).
If hypothetically, SSB and Mario bomb (I don't think this will happen), you have to evaluate everything related to wii-u, and what the right move is which could be moving all the software to 3DS, and or put other projects on hiatus that aren't feasible for the 3DS or something.
I don't think endlessly supporting a dead console with high dev cost software is a good or smart thing if your heavy hitters fail. Nintendo's had failures before (Virtual Boy), and recovered from them.