One of the most important things and also a leap, both in terms of emulation and the hardware itself, would be some homebrew that overclocked the console. I believe that only that would help and pretty much everything we use on our old wii U
Are you willing to destroy your machine? Since that would happen. The processor oe WiiU simply wasn´t made to be OC`ed since it allready runs at max speed.
Well, under the assumption you won´t give it 1.5 or 2 Volts or something like that. Another big problem would be the low power-delivery which is only able to handle 50 Watts on WiiU.
i even heard from a game´s developer of WiiU now, that whenever you use the Wii-shaders (aka the TEVs) in the WiiU-mode (yes this is possible guys), the processor seems to be limited to running at 729 Mhz too. He specifically said he had to downclock his processor in his notebook to 800 Mhz to do what the downclocked WiiU-processor does in this mode.
And i heard this seems to be because the Wii-GPU consumes a lot more energy then the AMD-Radeon programmable shaders and it gets very hot (hotter than today´s GPU get when you have the same amount of shaders). And when you use that Wii-GPU to use that in a WiiU-game (e.g. via Unity), your processor will simply not be running at full speed in order to not damage it and/or consume more than 50 Watts which the system can max. deliver.
You should know the WiiU´s Processor doesn´t even clock itself down like any other processors today do it to protect themselves from overheating or because they simply want to save on power. It allways runs at the same, full clock-mode it was adjusted to (GC-clock, Wii-clock or WiiU-clock). And the type of game/applications tells the processor at which given full speed it has to run. The whole time.
And even if you would get...let´s say a 10% more Mhz out of if (so instead of 1.25 Ghz you now gain 1.40 Ghz = 125 Mhz faster)...it´s still only 10% more speed. You wouldn´t even notice that difference...
Yet you consume a lot more energy by just getting 10% faster. Since those processors consume a lot more energy the higher you clock them.