that would mean making controller patches which no usbloader does, its possible but i doubt it will happen tough.Support for the GameCube Adapter wouldn't be specifically for USB Loader GX's Menu but for Wii games that support the GameCube controller, I.e. the WWE games, Sin and Punishment, Tatsunoko vs Capcom, DDR, so on and so forth.
that would mean making controller patches which no usbloader does, its possible but i doubt it will happen tough.
not really im preety sure like in nintendont you could find the patterns most games use to call the gamecube controller and such but it would be a big project, Fix94 considered doing one where wii U pro replaced CC in wii games but he never started it sadly.Each game would have to be patched individually