I could answer, but I don't know how important it is. At the pitch level, this question isn't really the issue. People have been dreaming of VR pitches for decades...partly why the possibility of real VR has captured the imagination of so many people.

At a more tactical level, such as beats, storyboarding, and even UX research...there's still a lot of experimentation when it comes to what works and what doesn't for storytellers. If you tell an experienced director to make an action movie, there's a lot of well understood techniques they can lean on to tell good story. So far, our experiences show that a lot of that flies out the window with VR unless you spend all your energy trying to encourage your user to frame the shot the same way a director wants you to. However, if you do that, you aren't really using VR anymore.

The problems that constrain story length are really a problem because you can only give story so much depth in 15 minutes...and if you don't have the opportunity to figure out how to tell a story with nuance, you won't learn how to get nuance right. VR has no nuance at the moment.