As I look at what I have in my first draft of When We Were the Kids, I have begun reading a book on somebody I barely knew and barely knew his music. Warren Zevon, the subject of the book, I'll Sleep When I'm Dead, is the person. Other than "Werewolves of London" and his final record, that's all I really knew about him going in. That's why I'm reading the book.
As a writer, you can engage your readers way more when you go beyond talking about how awesome somebody's music is. All opinions are subject, so do you really want to devote a lot of space in a biography talking about how awesome the second album is better than the first album? There's a place for that stuff, but I don't think large chunks of space should be devoted to that in a book.
I still stand behind the notion that you should examine more about the people you're profiling instead of the music. The music should be mentioned, but this not a glorified essay meant for liner notes. You get a better understanding of the music when you know more about the people behind it.
So far, I've enjoyed this take on Zevon's life, as told in the oral history format with a number of people that knew him well. The emphasis is more on Zevon rather than talking about all the specifics of his music. The music is there for you to listen to if you're curious. I like that option instead of being bombarded about opinions about his music.