let's be real, it was absolutely the game pad.
No reason to retcon the obvious truth.
The game pad was a pure gimmick, a gamble that the big thing that gamers wanted was a way to keep playing when someone else in the family wanted to use the TV. While I'm sure that's an issue for some people, it's not an issue for many people, and that seemed to be the whole reason behind the entire design of the system lol. It was all just extremely poorly thought out.
And yes it made it so you have this awful awkward asynchronous gameplay where one person has the game pad and everyone else uses last gen controllers. I remember when hearing about the system before it came out and finding out it's just a single giant controller and all I could think was that's a bad ridiculous idea lol. While N64 was THE multiplayer system of its day, and GC was a good multiplayer system, and Wii had fantastic casual multiplayer games to bring everyone together for a night of gaming, the whole design of the Wii U screamed "this is a single player console only and it's gonna be awkward weird different controllers asynchronous gameplay if you want to do multiplayer".
And then of course it jacked up the price of the system and hurt its specs all for the sake of this gimmick nobody wanted. Whereas the Wii saw Nintendo stop chasing power to do a novel fun new way to play games that was also affordable, WiiU saw Nintendo do low power again but just to make a far less affordable system with a bad gimmick that did nothing to create novel fun new experiences. The whole async multiplayer is something that maybe a handful of games could work around, it's not what you base a mainstream system design around.
So the game pad made the whole concept of the system awful, jacked up the cost, kept the performance low, made multiplayer weird, and introduced nothing fun and exciting, all for a gimmick few people wanted or found useful. Add to that the fact that nobody was making games for the thing - probably because consumers and companies alike were like wtf when they saw the system so everyone knew there wasn't gonna be much market for it's games. And the cherry on top being that it was a successor to the Wii but years after the whole crazy Wii fad had died out, so the one thing it tried to have going for it was already over several years hence by that time.
So yeah, it was absolutely primarily the game pad.







