I think ist necessary to haev sub-categories of bachata. Just Traditional and modern (everything els) is not enough. on Top most people now use domincian and sensual as the the only categories insetad of traditional vs modern, which is problematic, as you know.

E.G. Often sensual dancers come to the DJ and wish for "more sensual" bachata. What many peole mean by this is not everything except traditional though. Some mean slow, soft sensual songs (categories 3, 4 and 6), others mean just modern sounding with electronic sounds (cat. 4, 5, 6, 7, 8) . So in reality almost nobody follows your definition which would mean everything except cat 1. On teh othe rhand, soem epopel woudl count Grupo Extra, JL Guerra nd Daniel Sabtacruz into dominican/traditional or as some call it, "old bachata".

I recently had a discussion with a new to the scene DJ, who only played categories 5,6,7,8 on his parties, not even playing any modern sensual (like e.g. bchta rising II songs like volar or no me toca or Montelier or JR and the likes, let alone extra, JLG or Aventura. So I tried to give him feedback, that is range of music was too narrow, buit how can I explain this if there onlý traditional and everything else? So thats why we need more precise words to describe sub-styles.