I was just in Tokyo last week and was staying in the Ginza district where this is displayed. Something like this is not really going to be practical for storytelling type of filming. It would be best for video games for the kids and other types of programming for adults.
While the applications where it would be cool are out there, like sports, the reality is the filming would be impractical for most if not nearly all sports. I just don't see this hitting mainstream.
The issue I have with allowing the viewers to control where they focus their attention is it takes those away from the director and into the hands of the viewer. Some people want that freedom, but they are simply ignorant of the consequences of such a transfer of power/control over the story. I do not think I can tell a story better than Steven Speilberg and if I went to one of his movies, why would I want to direct the camera instead of him?
These things are the video equivalent of the old "Choose Your Own Adventure" series of books. Sure, as a concept they worked, but you would NEVER get Shakespeare quality of story telling with that - the only way that would happen is if your choices are limited and the writer had realistic arcs that could go one way or the other and filled them out for each path as the story forks. In that scenerio, you are having the writer make lots of stories and are just choosing which one you want during the reading and your choice might not be the best one, like choosing to have Juliet wait long enough to discover Romeo wasn't really dead. They run off and live happily ever after. Sure, sappy happy ending, but not the classic timeless story that has shaped our culture for centuries.