I know my opinion on this doesn't really matter but I just made an account to say I agree with the others in saying that full rebindable controls would be great.
There are currently five unused buttons on controller and three missing weapon hotkeys. There are enough buttons to have full weapon hotkeys and a map follow mode toggle.
You could even add Turn Left, Turn Right and Strafe Modifier binds (left unbound by default) so speedrunners could try to SR50 on controller.
If I had full customizable controls I'd personally put Use on one of the bumpers, the map on Back and use the face buttons, the sticks and the remaining bumper for weapon hotkeys.