I saw other people talking about this, but it was dismissed because the Steam Controller supports XInput. Hover, the steam controller actually has 2 extra buttons on the back and a gyro over typical controllers, and the D-Pad and left joystick are also touchpads. I think Dolphin could really take advantage of these (especially with the Steam Controller's toggling profiles), possibly even giving the ability to emulate every part of the Wiimote-nunchuck combo.