So randomly generated music instrument. Awesome, right? Yup. Toady, you built an awesome system that creates fun and interesting instruments.
But from a story perspective it might be kinda bad. See, a trumpet have a lot of emotional context to a player. Being the best trumpet player in the world sounds awesome. We can easily imagine it. It naturally awake emotions cause we have experiences connected to that instrument. But there is no emotions connected to vimes. If I tell someone how my character is a legendary vime player it does no awakens the same kind of imagery and emotion.
Oh, its a lot of fun to come up with what a given generated instrument looks like and work. But take dragons and forgotten beasts. The forgotten beast are cool. But they do not hold the sway a dragon have. I constantly try to capture and breed dragons. I want to tame them, to ride them. But forgotten beasts are just beasts that needs to be dealt with. They are dangerous and scary, but they do not hold the same emotional investment as dragons.
I do love all these systems and sometimes I want it all generated. But sometimes I want things I am familiar with. So what I suggest is that we are given option to decide the degree we want something to reflect real life or be generated. So when set closest to real life it only generates real life variants. When set fartest it completely generates everything. In the middle it may do both, or use real life names and use real life example as basis that then generate a bit variation on those as templates.
And not just for music instruments but also for any other procedually generated aspect of the game. Like werebeasts. It can go from only werewolfs to any imaginable were-entity. And whose only weakness is silver to random material weakness, to completely random weakness. And perhaphs also generate the trigger for transformation.