A proper sound system

I would like to advocate for a proper sound/music system in Minecraft, that mapmakers/developers can add at will.

This basically allows developers, mapmakers, and even the composers that Minecraft hires to make their ambient music) to put in custom sound effects and soundtracks, and not need to constantly find ways around the very barebones sound system that seems to have been in place in Minecraft for a really long time. For mapmakers in particular, file sizes can get massive due to the kind of music they want to put into their maps, and having them play at certain times when a fade-in/fade-out would work best, ends up just getting cut short, leading to things just not sounding really nice.