I would like to be able to have custom instruments, like more detailed info boxes when you have a part selected. So I can have several boxes open at once to see things like how different fuel tanks are doing, how well different parts are doing. Like I can have several boxes of one jet engine up, one could be a meter for rpm, another could be internal temperature so I know when to throttle down to prevent overheating or something like that. The command pod could have things like a speed meter option, altimeter option, and maybe an overall fuel meter.
And what instruments I have can be toggled if I want to hide them, and they would be saved for each aircraft.