Well for one thing, Classic controller don't feature clickable Analogs like pro controller, so if games use that, you are out of luck. Just wanna point that out. Most games on wii u that don't need such a thing can use the classic controller i assume like super smash bros, maybe pokken tournament and what not. But don't quote me on that. If the back of the game case or eshop description doesn't say it supports classic controller then i guess it won't. Only homebrew I know that may help is the gamepad to HID which basically makes a usb controller act like the game pad, so depends on if it helps or not is subjective.