Probably not the first to come up with this idea but I was thinking the other day that it would be super cool if we could find & equip instruments like weapons & level up a skill line that unlocks new songs. Each instrument has that instrument's part of the same songs so players can time it & play together & the quality of the instrument could even effect how it plays as in white level instruments are slightly off tune. Could even have the voice actors that recorded the voice we get to choose in character creator record singing the songs & have lute players sing. Guilds could have talent nights, players could put on performances for gold & even the people who think such an RP thing is stupid would still benefit from selling rare instrument drops.
"Fear leads to anger. Anger leads to hate. Hate leads to suffering" - Yoda