1) Why do you want the state out of the config file? It's quite convenient for me to have it all in one file.
2) tap and hold does nothing at all.
3) flash obeys the scene mode.
4) Sounds like a good idea. Not sure how to fit that in the UI though. I think it should be part of the bottom toolbar but there is not much space... But really, I tried decreasing the brightness of my N950, pointed camera to a big lamp and it's not really bright at all. BTW: You have really weird use-cases
But how often do you access the settings ?