I'll side with Cobra on part of this issue. The OP posted: " How about a clickable day/night toggle that can be added to the instrument in the regular map view? "
Since he said "can be added" it implies, at least to me, that each user would have the choice to add, or not, this day/night toggle, presumably through the "Customize Instruments..." feature.
As for the automatic setting of day or night. I would think it should be something we could add, or not, on an individual basis. Mostly I want this feature because it's very distracting to be flying at night, have my iFly get a power interruption, shut down, then restart in the very bright daylight setting. Since it's already been discussed, and rejected, to have the iFly restart in the last day/night mode that existed when it shut down, having an automatic setting based on time of day would be (IMO) a desirable feature.
As for the originally requested Instrument 'toggle" I would be in favor of this. Being able to push one button while attempting to preserve my night vision (as opposed to 2 more button pushes) would be better.