Here's an idea for a (hopefully) minor change. I'm not sure what others think about it, so I'm throwing it into the fray:
I usually play with music switched off (some of the songs, especially the Christian choruses, get on my nerves after a while). But if I switch music off in the game options, then this mutes not only the background music, but also the diplomacy tunes and all sounds of the wonder movies. However, I like the flavor of the diplomacy music, and watching muted wonder movies is frankly silly.
So I'd like to suggest (if it's technically possible) two options:
( ) Activate movie sounds when "Sound Effects" are activated
( ) Activate diplomacy sounds when "Sound Effects" are activated
Then, if before diplomacy is entered (or a movie displayed), check if "Sound Effects" is activated and "Music" is muted. If yes, then activate music for the duration of diplomacy / the movie, and mute it again afterwards.
The reason I suggest tying this option to "Sound Effects" is that ideally there should be only one place where players change their sound options. When people want to change their sound options mid-game, they shouldn't have to think about where to go to do that. Therefore, the options above are designed as "set once and forget"-type options. You set them once, and if you don't want to hear diplo music or wonder sounds anymore, you can do this from the regular audio menu by disabling sound effects (chances are that if you don't want to hear wonder movies, you want a very quiet game anyways).
I do have a hunch that the functionality required for such an option rests somewhere in the exe though and is not available for modders.
What do you think? Would such options enhance the playing experience (I really think that muted movies are a bit silly)? Would it be possible to implement such an option?