Roger Ebert has Walter Murch's letter about why 3D gives people headaches ... and more importantly, why we don't need it.
And lastly, the question of immersion. 3D films remind the audience that they are in a certain "perspective" relationship to the image. It is almost a Brechtian trick. Whereas if the film story has really gripped an audience they are "in" the picture in a kind of dreamlike "spaceless" space. So a good story will give you more dimensionality than you can ever cope with.Who's Walter Murch, you may well ask. Roger Ebert says he's, "the most respected film editor and sound designer in the modern cinema" and then goes on to quote credentials.
Murch is also very good at explanations. It is simply put, well illustrated, and fairly short. I didn't need the letter to not care much about 3D, but for those who want proof, the evidence is ample. Go read it all.