First, let me qualify my response. I have read the book Wicked, and it was terrible. Despite how poorly it was written, how boring, and how meaningless the whole thing was, I still did read it through to the end, and when the end of the novel occurred, I felt like I had completely wasted my time (and a lot of it, since it took a long time to read). Naturally, I was not certain the musical would be any better, but I'd heard good things, so my hubby and I thought we'd try it (buying the cheapest seats for the production, so we wouldn't be too disappointed).
The good news? The musical retained few elements of the novel--very few--and invented all sorts of other elements, including changing relationships, changing the ending completely, and taking all sorts of other liberties with it. The characters were infinitely more likable and accessible, and they were funnier (which wouldn't have been hard, since the characters weren't the slightest bit funny in the novel). In fact, Glinda the Good Witch was pretty hilarious and stole the show from Elpheba (The Wicked Witch of the West) pretty handily.
The bad news? Well, it wasn't a very good musical. The music was pretty forgettable (I'd seen the most dramatic part of it on the Tony Awards, but I'd forgotten it completely). Plot lines were slim, and the ending was ridiculous.
Even worse, were I the novelist who penned the original novel, I would have run out of there screaming, and I would likely be in jail for killing the first person I saw. I imagined one of my own novels being turned into utter drivel, and the prospect of it made me cringe. Right now I am still cringing.
What's oddest about this is that I hated the novel--it might be one of the worst novels I've read in years--but I am still defensive about the idea of someone's work being mauled to death for the sake of a musical format. I can only compare it to the travesty that is Disney's The Hunchback of Notre Dame. What Disney execs were thinking when they took the most depressing novel ever (and one I personally love) and turned it into a children's cartoon will be forever a mystery.
And so will Wicked, I'm afraid. Still, it was fascinating to watch and analyze, from the perspective of both a novelist and a playwright.
Rather like a train wreck would be fascinating to a railroad engineer.