I've actually heard Disney acquired the rights to the Chronicles of Prydain. It makes me wonder if they're going to do an episodic series or will it be a film franchise?
I've seen the Disney The Black Cauldron, which I'll admit it's not the best Disney movie, especially when compared to The Little Mermaid, Beauty And The Beast, Aladdin, and The Lion King. I think it was a combination of The Book of Three and The Black Cauldron.
Chronicles of Prydain was inspired by Welsh mythology, and it's almost like a light hearted version of Lord of the Rings. I don't know how a franchise would work. I think there's one book that's more like a side story. If I remember correctly, Taran Wanderer is more like a side story, much like The Horse And His Boy is for Narnia. So I don't know what Disney is going to do with Prydain, a film franchise or an episodic series.