I just wanted to know. because I like the way of how it works. and if not, hopefully its gets implemented.
Bleeding Edge supports controllers but you will need to edit the qt-config.ini file to use it. See this for more info. Assuming that the Wii U Gamecube adapter uses directinput, it should work. Note that the config mentioned is meant for Xbox controllers (xinput) but I’ve tested it with my Xbox One controller and Logitech Rumblepad 2 (directinput) and they work fine (buttons might not match up so you will have to change it).