In some ways I find the mouse to be a much more advanced device than your typical game controller, ... It is generally easier to learn because of the visual nature of its interface and has far more consistency across applications. The mouse is still rapidly changing (more buttons, mouse wheels), in a sense it represents the evolution of a new language based on micro-gestures of your hand and fingers. Whatever the device is, I think this new spatial/gesture language represents the most probable future of input devices.