There are many other Roald Dahl books that are screaming to be musicalised. Why choose one and adapt it for the third (fourth if you count the opera) time? It has had an opera and 2 movies made (both of which could be considered musicals).
Matilda is much more adept for adaptation, I think.
Oh well - at least it's Shaiman doing the songs!
Nick Hutson
Co-Presenter/Producer
MusicalTalk - The UK's Musical Theatre Podcast
http://www.musicaltalk.co.uk