Yes, you do need a Wii U Kit. You cannot build, deploy and run your game on a regular Wii U console.
As Noctrine pointed out, there's no way Nintendo will let you publish a game that hasn't been tested on a console.
Wii U dev kit specs
The Wii U dev kit specs first and foremost support everything the regular retail Wii U console supports, and has the ...
This is a question best answered by Nintendo themselves. I have a suspicion that Nintendo isn't interested in people making games just for fun, since it can potentially hurt the Nintendo trademark. They want the name Nintendo be associated with quality, or seemingly quality.
Wii uses 3 mechanisms to track its controller:
infrared LEDs placed in a sensor bar
gyroscope (introduced in MotionPlus remotes)
Basic implementation was a simple optical calculation of remote's orientation using infrared-sensitive "camera" on top of a controller.
With MotionPlus gyroscope and accelerometer work together (similarly to a ...
The other answers spell things out in the ideal cases. Most code is common for games, and a clean abstraction layer is used for hardware/platform dependent parts.
However, many games have ports done by an outsourced company, and code diverges significantly. This is especially true with the consoles, but also common of ports to OSX or Linux from Windows.
Just to mention:
Since I posted this question, I went on the official website to register as an "official" developer.
I could get their approval in less than a month.
I think the commercial situation of the WiiU is so bad that they are ready to let anyone try to make great games.
But I still need to buy or rent dev material which is a bit expensive for ...
I tried to look into the UniWii library linked in the question, but the Windows download page appears to be a broken link at the moment, and forum threads about it are mostly 4 years old. :(
The basic idea it uses, a native plugin DLL referenced from C# with [DllImport] mappings, is a good one. I've used this successfully for interfacing with the Kinect and ...
There are some problems with doing this, specifically with the new model of wiimotes that Nintendo has released and has seemed to use to replace the old model. There is a lot of open source code available for setting it up though.
Here is a link documenting some of the new wiimote plus issues: