I always read stories about pilots when action is imminent, charging up their guns, flipping on their gun sights, removing the safety, etc.
I think it would be cool to have to manually turn the gun sight on and have it brighten slowly (were they vaccuum tube based?)
I also wouldn't mind a gun safety switch - I think once or twice during the last scenario I accidentally fired my guns - I don't remember exactly how or why it happened, but in a tight formation that could've been very very bad.
Maybe the two functions could be combined into a single switch.