Completly agree!!!
Just because Nintendo killed the console and alreally reached its EoL doesn't mean its homebrew scene should also die, and I feel pissed off that respectful hackers like derrek, qlutoo, smea and yellows8 make comments like "after all is just the WiiU", "wiiu=meh" or "if you still care the wiiu" which just makes other devs to stay away from develop cool stuff on such kickass machine. I don't mind if those guys don't want to support the WiiU anymore to look forward into the Switch (come on, they alreally did too much for the WiiU, even derrek helped hexkyz to exploit the boot1) but making such disgusting comments is not good.
I can't help but wonder what could be accomplished with a hacked out Wii U with enough people looking into it. One thing I'd love to see just to say that the scene got it done when Nintendo never did, even though they themselves advertised it at one time: getting 2 Gamepads connected to a single system.
And the best piece of homebrew I could imagine to show this feature off would be emulating up to 3 instances of GBAs at once. This shouldn't be impossible, the OG Wii has a little known homebrew called GB4GB which allowed up to 4 GB/Cs to be emulated at once on one screen. And the different instances of emulation could link up, me and my buddies played the original Pokemon games at the same time this way and even did some trades and battles together, it was pretty cool. But with the extra power of the Wii U, I would bet that 2 or even 3 GBAs could be emulated at once. And if we could have each GBA show up on one screen each: TV, Gamepad 1, and Gamepad 2, that would be amazing, and then if we could also link those up for multiplayer GBA games, that would be amazing. I loved the multiplayer GBA version of classic Mario Bros that came with every Mario Advance game, that was a blast, and there are a lot of other great GBA multiplayer experiences that are not getting the recognition they deserve in this day and age.