I think that's what they are going for. I do think the set is all wrong and that the La Jolla production missed the mark, so yes, I do think the set is too small. Maybe it will be different in the next out of town tryout.
Countdown til Jordan comes on raging about how much loves me! 3..2..1...
The set was not small in person. If they do get a bigger theater on Broadway, chances are they will just open it up a little bit more. Otherwise, I don't expect producers to pony up the money for grander sets. Hunchback is a hard sell in the US, despite the few vocal fans.
"If nothing's moving, etc. The kids will be bored."
I've done a lot of children's theatre and I think a lot of people underestimate young audiences. If the story is engaging and the music is good you'd be surprised at how attentive a young audience can be. They are not usually the ones who need to see "grandness" on stage to keep their attention.