The set is large, but not Palladium scale, I think it could do well in a Savoy/Shaftesbury size venue. The unit set is three vast, classically architectural walls, all of which are gauzes so things can happen behind them, and projections can be shined on to them, although this does change when the more... magical elements come along, which I really don't want to spoil, and there's a lot of automation to create the various settings, and there's a full size facade of the Duke of Yorks that comes down at one point. However, I think the scale of the show, and the special requirements that they said the Curve could provide must be a lot to do with the flying, which is very impressive, and integral to the plot.
I loved the movie, but I think they've ramped up the drama, and added a lot more of the real life story of Barrie
(i.e. Sylvia having doubts about his intentions with the boys and her, him never being able to grow up because of the death of his brother and lack of love from his Mother, and also introduces his group of famous friends as a sextet.)
However, I believe the story that the musical tells is a much more engaging and dramatically interesting one than the film. The biggest change, however may be the increase of role for Mary, Barrie's wife, played by the fantastic Clare Foster, whose character now actually has something about her, and who actually meets the boys and Sylvia. Although in Act One, she comes across as a selfish, spoilt character, she redeems herself in Act Two. Regarding the musical comedy quote that a lot of people, myself included, have worried about, I would say its a musical comedy in the same way that Oklahoma and the classic musicals are comedies, in that there are comedic parts and tragic parts, but you do go out of the theatre feeling uplifted, most definitely. If I was to compare it to anything, it would have to be the Rogers and Hammerstein musicals: there are no modern belty numbers, just a lot of songs that help develop the plot, some of which are fun and joyous, and some of which will break your heart. I wrote on my twitter last night that a "classic new musical had been born", and I still agree. I don't know how it will do commercially in London, but the show is most definitely a crowd pleaser, and I can see it being the kind of show that will get terrific word of mouth and maybe, I hope, succeed in finding the audience it deserves.