Hi Magic Lantern,
I would like to propose one feature, that is frequently used in astrophotography - "DarkFrame". A dark frame is an image captured with the sensor in the dark, essentially just an image of noise in an image sensor. This is achived either by taking picture with the lens cap on or if the sensor is equipped with shutter, by closed shutter. From the ML menu this feature could look like simple "disable / enable" flag (disabled as default):
DarkFrame = [Disabled/Enabled] or [Off/On]
When the DarkFrame is enabled, both the mirror and the shutter should be locked in the "closed" position before and during the picture --> which is the only challenge in implementing this feature (I don't know if You are able to control them independent from "taking picture" functionality as such).
It is important to ensure that the DarkFrame functionality can be used together with BULB and INTERVALOMETER --> the two main ingredient for astrophotography.
Some sources for DarkFrame knowledge: