i'm not able to program anything and so I don't know what is simple and what would make a big...
But I think the headphone feature is just the missing menupoint (With zones most of the technical work is done)..and I don't understand why the developers ignore this wish to play music on a party and prelisten it quickly since 2 versions of this wonderful program. I for myself have a pub, and I wished to use this programm in live equipment since years, and the only reason why not was this missing feature. So I sortet everything with mc and used a professional dj program just to play my playlist and beeing able of prelistening.
I cannot understand,that the developers wouldn't see the benefit of having their mc running in severel "pubs" "shops" etc....I was min. once per day (when i was sorting music in background) asked by a customer "what program is running there and playing the music"..so it's free advertisment