I had a dream last night, I was playing FC3 somehow and of course in the map editor.
One key thing I remember from it was there was an option to choose from like 20 different "Ambient Tracks" and then you could also set the Ambient Track's volume. There was different ones, like: "Spooky Night" with owls, crickets and wolves howling. "Beachside" with seagulls, breeze and gentle waves heard. "Stormy Wind" with rough wind blowing and rustling. "Warzone" with constant background guns firing, bombs going off, ect.
They went on like this, and being able to choose the volume really let you set a mood for your map. There was even other alternate versions with a music track playing for even more mood, such as "Spooky Night +Music" with eerie graveyard themed music playing over the Spooky Night Ambient.
I really wish this could actually happen, it would be such a great little option that would make a huge difference when playing.