If those buttons return a resistive value when pressed, then making the wires significantly longer might cause the controller to not recognize the buttons. If the controller is looking for a specific resistive value and the added length of wire changes the value enough, it won't see the correct value when the button is pressed. Do you have a multimeter or more preferably an oscilloscope? Without knowing exactly how the controller works, nobody can give you accurate advice. Those wires are small, so they do not carry significant current, but without more information we're all just guessing at this point.

masusaca, what are you trying to make where you need to move these buttons off the controller?