You can already add user-defined genres like the ones you named.
Also, there has been an update in the genre list, see Subgenre Option
Also, it may be worthwhile to check out the id3 standard https://en.wikipedia.org/wiki/ID3.
You can already add user-defined genres like the ones you named.
Also, there has been an update in the genre list, see Subgenre Option
Also, it may be worthwhile to check out the id3 standard https://en.wikipedia.org/wiki/ID3.