Hey there chaps. So I was wondering about the yet to be implemented system of Music and perhaps poetry, but I feel my idea could overreach to all art works.
See it would be simple to add musicians, and when they play they create a happy thought, but this would be boring, very gamey and also not very FUN.
I say Music should be picked up by highly creative dwarves. Depending on their likes and dislikes they would create songs on parchment. These songs would differ in quality, obviously, but also in themes. So if Urist McSlateandRoll were to pick up the guitar and sing he would probably sing about his favourite material, Slate, or his favorite animal. People who share the likes would like this song and it would create a happy thought depending on the quality of the music. If one of the listeners does not like Slate at all, it would create a negative thought. (I feel that if a musician makes a song about his dislike it should appeal to somebody who also dislikes the subject as the musician would probably write a song of disdain).
Because of this chaotic nature of music and poetry, it would be recommendable to keep your musicians in check or try to force them out completely, because if there is a great singer who loves to sing about cockroaches theres probably going to be a lot of pissed off dwarves. So you would have to try to destroy copies of this song. On the other side, if the song is of great quality you might want to reproduce it on parchment and sell it to travelling bards, increasing the Fame of the original write and your fortress, which creates happy thoughts.
After having created enough music works, paintings, and art pieces a fortress could rise to become a cultural centre, shaping the culture of your civ or possibly your world. More musical Dwarves would flock more to cultural cities and be happy about living there. (I also feel that a craftsdwarf fortress should naturally attract more craftsdwarves, a military fort more military dwarves etc.)