Updated: May 12, 2022
Back when the Wii U was released, it was met with a lukewarm reception, and for good reason. The Wii U was a relatively substantial hardware upgrade over the Wii, but the problem was the Wii was extremely behind in terms of hardware oomph to begin with, meaning the Wii U being "more powerful" wasn't saying a lot... and it was really more on par with previous generation PS3/X360 consoles than the modern PS4/XBone's of its generation.
The Wii itself was just an incremental upgrade over the Gamecube released in 2000. The Wii had roughly 1.5x the hardware capabilities of the Gamecube, yet it was more than 6 years younger.
On top of that, it came centered around an extremely bulky and gimmicky screen-based Gamepad only good for 1 player (the system would only allow 1 screen-Gamepad be connected to it at a time), leading to some really weird multiplayer social dynamics when friends had to decide which unique controller to use (eg. a Wiimote or a screen). The built-in 720p screen was very low quality too, and having to pull out one of 3 or 4 controller variants for each game you played was a real headache.
Either way though, even the well-intentioned 'innovative' controls really couldn't counter the archaic system specs by the time the Wii U released.
^So (TOO) many options!
What was nice however, was that it was a drop-in replacement for the Wii as it was backwards compatible with the full Wii library and all of its accessories. Plus it (FINALLY) supported 1080p resolution... although again, this was in 2012 when 1080p was a common commodity- the competitors had already been spec'ing their systems to render at 1080p for nearly 2 generations, plus the upcoming (in 2017) PS4 Pro/XBone X supported 4k and were still technically within the same generation of consoles as the Wii U.
All of this, combined with a lack of focused marketing and lack of 3rd party developer support I believe led to a whole generation of gamers that went "uhh, what does the Wii U even do that I can't already do with my current/old consoles?" and "My TV's a screen, why would I want another screen? Plus stylus controls are awful, why would I want to tap a display when I could be pressing buttons?"
But fast forward about 7 years, to where the Wii U is now obscure and all but forgotten since the dawn of the far more successful Switch in 2017, and what can we do with it? Well, it turns out, a LOT. It's an affordable, easy to find, unique console with enough horsepower to run every Nintendo came since the NES, it's extremely moddable, supports 1080p, external disk drives, a wide variety of controllers, and has been hacked up the ying yang.
Enter the Modded Wii U. In my opinion, there is no home console in history that has been a more perfect fit for being a retro gaming center than this device. Raspberry Pi's? Not enough power. PS Vita's? Awesome, but I wanna play on the big screen and with multiple controllers. PC's? Try streaming OpenEmu or Bigbox to your TV, no matter how nicely you've set it up- maintaining those controller configs, USB registrations, and screen output settings every time you restart... no fun.
The Wii U is first party Nintendo hardware though! With Virtual Console games specifically ported for play on the Wii U, meaning native, true-to-spec performance! So if you're looking for a dedicated console capable of letting you play every title ever made (excluding modern Sony and Microsoft consoles) without the hassle of jury rigging/mapping wiimotes and retro controllers to each game, this is the rig for you.
The setup process for hacking and building out your Wii U just the way you like it... well... it's not quick, and not super simple- but it's well worth the effort. This article isn't meant to be a thorough step-by-step tutorial but more a repository for all of the references you'll need when modding yourself, in an effort to minimize googling- plus some of these guides are hard to find and helped tremendously when I was modding. I'll link the main videos I used to assist me through this process below:
Pretty complete text guide to everything Wii U:
Site from the guy who put together a ton of these videos:
Hacking your Wii U to run custom firmware Haxchi (for all of the mods below) with persistent mod:
Hacking your Wii U to run the Homebrew launcher:
Putting the Homebrew launcher on your Wii U homescreen:
Manually installing homebrew apps (downloading from your PC instead of the Wii U itself):
WBFS Manager download (for extracting Wii games for use on the Wii launcher)
To play any Wii U/DLC/Virtual Console game you want, you really just need an external hard drive and Wii U USB helper. This app lets you download Wii U games, DLC, and virtual console games to a hard drive all in one interface- then you plug it into your Wii U and have a whole library to choose from:
For Wii U games, you shouldn't need any mods above- just the USB Helper app on your PC and a hard drive. For other games, you'll need an SD card with the homebrew app, Haxchi and any other app required for whatever system your games are for.
To play Wii games with an amazing GUI like you see in the video, you'll need to launch Wiiflow from the Homebrew app:
Some notes on Wii U modding maintenance:
1. An external 2.5" hard drive needs more power than the Wii U outputs from its ports, so you 'll need a cable with those 2 USB outputs you see that come with many portable hard drives, and plug both into the USB ports on the back of your Wii U.
2. If you unplug that drive for any reason and plug it back it in later (like if you're switching it out for your vWii drive), if you organized your games into any folders, they'll reset and be back on the home screen totally unorganized. It's annoying but it doesn't break anything.
For Wii emulation and Wiiflow, there's a few extra steps needed. You'll need:
An SD card under 2GB to install the homebrew launcher for the vWii
Plug in your drive that contains all the WBFS-based games into the TOP port on the back of your Wii U (that's the only port the vWii will recognize).
In Wiiflow, it will not recognize or work with Wiimotes with Motionplus. You have to use an original, first generation Wiimote to navigate the Wiiflow menu. After you choose a game though, you can pair up your Motionplus Wiimotes no problem and they'll work in the game.
If you use this tutorial and need more info, please let me know and I'll go into more detail and help you out.