So what do you think? Is the wii u a failure in concept or execution? Is it neither or both? Why?

concept

Execution... so far.

Concept. I just can't think of much the gamepad can really offer. Menus and maps are nice, but for how expensive it is, it's not really a great trade off.

Execution. I think the Wii U is a great concept, but Nintendo failed to follow up the launch window with awesome, compelling games, They really should have learned after the 3ds failure launch.

Their advertising is also horrible compared to the Wii

Not sure. It's considered to be a failure because few people want to buy it. Hm... Maybe it's a failure in post-execution? Because the initial line-up was superb and I thought it would carry the system till newer releases came.

Currently execution without a doubt.

Execution.
It's shown the potential to output great games, Nintendo just screwed up royally by letting it go 9 months without any big releases and doing an awful job of marketing it.

I'm going to say both, they really should have thought it out and studied market trend instead of just adding a popular application like a non multi touch tablet. Same could be said about the 3d on the 3ds.

Pikmin 3 is only out in Japan.