I dunno, I think it kind of makes sense. Although I'm not a music expert I think it's pretty realistically simulating what can be made with few materials.
I mean we have piccolos, drums, harps, flutes, and trumpets. Aside from the harps, the instruments are wind or percussion and not stringed (which wouldn't make sense, because all a dwarf takes to make an instrument is a piece of stone/bone/wood/metal, and not strings.
Personally I can't see a stone trumpet working out very well, but a stone flute might work.
Ok, so harps are the oddball, and drums would be better if you had to use like a layer of leather or something for them, but if we had things like pipe organs and such you'd assume they'd take a lot more materials.
I'd like to see stuff like the gigantic crazy pipe organ implemented as a building. I suppose it'd take some pipe sections, stone, ivory (lol ivory), and maybe even some mechanisms to make.
Or you could have magma pipe organs that use the steam created off of the magma vents to generate the air pressure, which would be plain awesome.
If we had all that, then we could have bardic dwarves playing music in certain areas that generate happy thoughts when dwarves go nearby. "Urist McPeasant has been ecstatic lately. He has dined in a legendary dining room lately, he has admired a superbly designed pipe organ lately, he has been soothed by music lately."
Whoo, sorta went off on a tangent there.