I am one of those people who will see just about any version of any Shakespeare. I applaud his vision to do something revolutionary with the Bard, and I will be first in line to get my 3D glasses to see this, or any other play he decides to render in this exciting new way.
But if the purpose of the film is to make it more accessible to more people, to find a new audience, I don't think it will work to the degree that Branagh would like.
Baz Luhrmann's Romeo and Juliet was very successful, and I enjoyed it very much. But even with it's rock soundtrack, edgy cinematography, colorful costumes, and very inspired performances with young actors, I don't think it increased the audience for Shakespeare as a whole in any significant numbers.
Baz didn't follow up the movie with further adaptations which would serve to educate and entertain a potentially newer and larger audience.
From the looks of the bookstores, there is a demand for Shakespeare, but the books I see more and more are the No Fear Shakespeare variety, with the full line by line translations into plain English. I also see the Graphic Novel adaptations of the plays, which serves the teenage audience, trying to grapple with Shakespeare for school.
So, as much I would enjoy a 3D Shakespeare, I think there is a demand for more than just entertainment. I think the demand is for more understanding, of Shakespeare's plays and who Shakespeare was.
I doubt that there is a very large audience who wants to see every last Shakespeare play without some sort of translation, and I doubt that this potentially larger audience would want to see a documentary about Shakespeare's life.
But if they were put together in an entertaining and fresh way, then I think there would be an even larger audience for Shakespeare than we have ever known before.
In much the same way that Amadeus told the story of Mozart while giving a survey of his music, my adaptations would tell the story of Shakespeare and present his plays. But while Amadeus had to make up the rivalry between Salieri and Mozart, my adaptations stay very close to the truth.
Finally, if the purpose of a 3D film is to make it immersive, then what could be more immersive than a film where you get to visit the Globe with an audience of nobles and groundlings to watch the very first performance of Hamlet, and starring Shakespeare himself?