I think the biggest problem is at the heart of the work. It is not a musical for children, but people think it is because the main character is a child.
Seeing the original production, the adults were moved and shaken, but there were children in the audience who could not follow the story.
Perhaps the piece could be adapted to make it more kid friendly, but I think that would destroy so much of what was wonderful. But how do you market an adult play based on children's literature, in which a child is the main character?