Adding a selector to cycle through detected joysticks or gamepads would be extremely useful, both for debugging joystick setups and for ease of use.
Right now it seems the joystick/gamepads are selected based on activity, however if you have a noisy joystick that is tuned through another program, the noisy one is selected with no way to select said quieter, tuned stick without fully disconnecting the noisy stick and restarting the game.
This is especially useful if you are running a full HOTAS setup that is being tuned and simulated as one controller in a program like Joystick gremlin or T.A.R.G.E.T.