Personally, I think 3.X has had some of the best tracks i've ever heard in any video game, Sophia's theme, the whole alex suite, the 3.4 expert dungeon boss music, Sohr Khai theme, the Niddy fight, I think the music in this game is getting stronger and stronger.
There may have been a drop in how much you enjoy the music in regards to personal taste, that's fair - not everyone likes the same stuff - but I don't think there has been an objective drop in prodcation quality at all.
