I agree very much with these suggestions.
Some users have been talking in other threads about using folders for ease of organization and access about Roll20 Handouts, Macros, . . . So, why not the Jukebox as well?
Right now all Roll20 Jukebox's sounds & music pieces are in a single, very long alphabetically sorted list, making very difficult - if your list of assigned sounds for your campaign isn't small - to just pick & play that very specific sound that you are looking for in midst of the game, at that specific time .
So it would be really useful not only to distinguish - by using separate folders, or by means of other method - music from FX sounds, but also to be able to arrange music pieces and sounds in categories or folders such as "ambient music", "combat music", "melee combat FX sounds", "magic spells FX sounds", "animal roars", etc.
Right now I have only 17 items in a Roll20 test campaign, and I can say that in midst of a game, it takes a while to find the cool sound that I assigned for a character fast-drawing a sword, for putting an instance.
Currently this sample list has just 17 items because it's only a test, but I know that I'll be adding many more sounds, making specific sounds or music tracks in the Jukebox really difficult to find in the suitable moment during the game.