I've played a bit with astronomical photography and the amount of work to getting the signal in the picture good enough without introducing noise is quite high. (Going as far as taking pictures with the lens on the telescope to capture the natural sensor noise, which is usually good for about a few hours of use)

However, you don't get second tries on a computer. If your signal is too weak or the noise is too strong, the picture is ruined, no amount of editing will fix that.

The only solution I'd see for that is to take multiple images at once with different sensors, each using a different exposure. But that still doesn't provide a sliding scale, only a stair function of "is this close enough"?

The better solution is to take a proper light meter and properly setup the camera in the first place.