Movies are a director’s medium. Directors have the last say in the script, look and feel of a movie, and the movie succeeds or fails on their singular vision.
This model of storytelling, however, does not allow for audience interaction or influence. You cannot call a director half-way through a movie and say, ‘you know, I think you need to add a character here or tweak this story there.’ How fun would it be to immerse yourself into a movie, deeper than the visual trick of 3D, and interact with the story? How satisfying would it be to influence the story’s outcome as a viewer?