Having made a real 3D movie, you realize that, right from the production design, you're designing sets that complement the 3D. You're designing interactive elements, like rain or smoke - all this particulate matter in the air enhances the 3D. But if you're shooting in 2D, you don't know about that.
If you work with a subject matter beloved by a hardcore fan base, then there's going to be a huge amount of discussion of what you've got wrong or right. In some ways, you can never please overly obsessive fans; it's just impossible. That doesn't mean to say they're not going to go to the movie and thoroughly enjoy it.