I get your point, but this is the best way it can be done. There's people who actually play multiplayer. If they would not have the files on their build, while the guys with the DLC would, they would not be able to play together. Add more DLC and you have got a community that is so divided there's not enough players for multiplayer.
I never noticed any new music whatsoever. I think that's what the music dlc is for.
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