It honestly depends on what you want to run. New super mario bros and a few others will reach full speed. If its just one game you wan’t, just test it out on android/lakka/ubuntu(disable vsync). I doubt trauma center will be demanding so id try it out for sure.
If you want to play heaps of wii games homebrewed, dont buy a Wii u, just buy a Wii. Wii costs about 10$ second hand while the wii u is an effing rip off at closer to 100$. On the wii u, you also need to spend more money to purchase an eshop game, which is then used to inject the homebrew app used to run homebrew on the wii u.