Two things contributed to the 3DS's sales boom - the massive price drop which made it affordable in comparison to other mobile gaming solutions and an onslaught of new games. The system's been riding that wave of success ever since and even though you can easily get PSVita deals that are just as good as the 3DS deals, the 3DS reached the level of popularity where it doesn't have to try anymore - it just has the market by the balls.
It doesn't take a degree to think of ways how to improve the Wii U situation at this point. It's not going to beat the PS4 or the Xbox One, it's a no-contest. The Wii U has to build its own niche and it has to build it soon because it's been on the market for 2 years now, in another 2 the hardware will become irrelevant and too poor for developers to care and in 4-5 it's going to be completely irrelevant as at that point people will start expecting a Nintendo next gen to come out soon.
I agree with you in most of you said, but my main point was, the name is the least of WiiU problems.
Xbox One also has a terrible and confusing name and is selling just fine.
Poor marketing, lacking of third party support and been vastly underpowered are much more
important factors to WiiU bad sales.
About the niche public WiiU should aim, that's what I disagree with you.
WiiU tried to have a niche public, the same niche public Wii had and made it a success,
the casual public. The problem is WiiU doesn't have the same appeal to casual public,
and there are far cheaper and more appealing options to casual public now such as smartphones and tablets.
It doesn't appeal casual public, nor hardcore gamers, it doesn't have a good quantity of specific genre titles,
to make it a niche console for some genre niches, and it can't gather those niches to WiiU since
they would need third party support for that.