I guess I just noticed today that it is extremely bright outside when the moon and/or stars are out and it's night-time.

I think it would lend a lot of ambience and immersion if it was visibly darker at night. Makes going out at night more dangerous, gives more reason for campfires at certain locations and lends realism to the world.

I know I'd be a lot less likely to go exploring or hunting if it was dark outside at night.