i think making enough genre categories is a problem in general.
because there's always more and more new genres being made, just take a look at metal for an example.
Metal, heavy metal, death metal, black metal, blackend death metal, brutal death metal, slamming death metal, technical death metal, deathcore, metalcore, grindcore, hardcore, post-hardcore, thrash metal, progressive metal, nintendocore, folk metal... and the list continues forever basically.
(having a shit load of subgenres usually causes arguements between users if said track is not accurate to what the uploader uploaded it as, and what the listener think it is)
the same thing happens alot of other genres. so i think we are better off keeping it simple.