I agree that it will probably be more of a Le Mis (French Revolution, kind of a serious topic for a musical) type of musical, than a happy-go-lucky one. From the appearance of the website I am guessing they will be going in about the same direction as the films, so I am guessing it will be quite serious. I am expecting a dark somber stage, and dramatic ballad type of songs. But the one question I have is how long is this thing going to be? They are most definitely going to be making major cuts (I wouldn't expect them to have dear old Tom B.) in the story because who wants to sit down for a 9 hour musical.
I just hope this is not a complete failure, but then I wouldn't bet on this being a huge success