I agree with most of your points.
I believe it just needs better marketing and better software pricing right now. The game library right now is good, there´s a few gems coming in a near future.
As for the controversial 3rd party relations, I think it´s a double-edge knife. They seemed so optimistic about the WiiU at first, then they just decided to abandon ship due to poor hardware sales and less possibility of good sales.
So it´s not all Nintendo´s fault on that front, since many games have approximately the same attach rate on other devices (Heck, a few games like Sonic AS Racing Transformed and Rayman Legends even sold BETTER on WiiU than on other platforms with waaaaaay larger install bases).
BUT, Nintendo could do a favor to the few companies that are still developing for WiiU and help them market their games. Why they never talk about 3rd parties games on their Nintendo Directs ? They should do it, that would help show consumers more variety on the game library
Essay Pro