Top left: current Gamepad, top view; bottom left: improved gamepad, top view; top right: current Gamepad, side view; bottom right: improved Gamepad, side view
If gamers enjoy a more tactile feel in their controllers, then one easy solution to making the Gamepad more playable is increasing the clickyness of the buttons. This can be achieved by increasing the button size and press distance, as well as the springiness of its return to normal height and the mechanical sound made when clicked.
Another solution is varying the size and shape of the buttons so that their form matches their function. A and B are more commonly used, so they should be larger!