Very good idea is to have smart playlist scheduler. For example you will have 5 folders: HOT, OLDIES, JAZZ, ROCK, SLOW and RnB . You could make " clock " - where will be written:
1 song HOT
2 song ROCK
3 song SLOW
4 song ROCK
...
...
12 song HOT
Playlist will pick up song from folders. There should be some restriction: for example not play same artist and you could choose time ( for example 90, 120 ) minutes.
This working in some internet systems ( CLOUD DJ etc. ) and I will be happy to have it here!!