The news is largely valued for its accuracy, timeliness, and topical relevance to a reader. Music and other cultural objects are valued for their enjoyment, which is contingent on individual personal preferences. I'm skeptical of a platform that would use domain-specific talent to create playlists for what comes down to individual personal preference. Domain specific talent makes much more sense regarding news where the relevance can be easily determined because it is largely topical, whereas the relevance for music is based on personal preference, which can't be determined through domain specific talent.
I'm also not convinced that more meta-tagging is the answer either. If I tag a song with a mood, genre, style, etc., it will help a user find that song based on those new categories. But in the end, finding new songs based on categories isn't that helpful because what matters is finding songs based on individual personal preferences. For example, I might know I want an energetic, intense, electro-rock ballad, but defining that domain doesn't guarantee I will like the results. People rarely like all the songs on an album, and as far as domains go, albums are very tightly defined domains. Likewise, using Uber-Dj's as domains don't seem to be the best answer. After all, their playlists are based off of their preferences, and, regardless of how much they "know" about music, unless their preferences are like mine, their list will not help much.