What people dislike about Wii U hardware?

[Illusion]

I do not agree that the Wii U had a poor first party software library, however, it took far too long for the Wii U to build a decent library and by the time it was built the console was already a long lost cause. There was a massive drought for the first year on the market where the Wii U had almost nothing except for New Super Mario Bros U. Nintendo dev's were openly admitting that they were having a lot of trouble developing games at 720p and so the reason for this drought was something that was quite embarrassing for the company and probably a big cause of concern for its shareholders. Furthermore, the 3rd party library was almost non-existent, which was another significant problem for the console.

It is no doubt though that the hardware was a factor in the Wii U's failure, but it is not the #1 reason in my opinion. Nintendo confused a lot of people by re-using the Wii name and showing people holding Wii-motes in the commercials where people were thinking that the Wii U was an add-on for the Wii. Also, the Wii U did not have a killer app at launch to show people how to make use of the game pad which is a big part of what made the hardware such a turn-off. If the Wii U had launched with a game like Super Mario Maker that clearly showed developers what could be done with the gamepad as well as clear marketing, I think that the console could have sold twice as well as it did even with the clunky gamepad.

That said, the gamepad could have easily been slimmed down, but the Wii U launch was such a catastrophe for the reasons mentioned above that Nintendo did not even see it worthwhile to try to revise the hardware or give a significant price-cut. By late 2014, Miyamoto was already teasing about new hardware which means that Nintendo probably made the decision to kill the Wii U well under 2 years into its life. The games that came after this point were just to satisfy the base that bought the console, Nintendo had no expectation that they would change the Wii U's fate. In fact, I believe that Nintendo released games like Smash, Splatoon, Mario Maker and maybe even Mario Kart with the expectation that they would get re-released on the Switch in order to make the investment in the game's development profitable for the company because the Wii U's paltry base was not enough to accomplish this by itself.