Roger Ebert wrote a controversial article about 3D, and I'm seeing a lot of things written about it, so, as a person who sees a lot (A LOT) of movies, I'll weigh in:
RE: 3D distracts from most movies
Q: When done poorly.
RE: Makes people nauseated/causes headaches
Q: Yes, but coupled with Dramamine, it's often ok.
RE: It is designed to force theaters and ticket buyers to spend additional money.
RE: It makes the film literally darker.
Q: I have heard this, but not noticed it as most 3D seems to be set in dark locales. I assume on purpose.
RE: It limits directors.
Q: So says Chris Nolan. So, I'm inclined to agree, being that he actually films films.
RE: It adds nothing "essential" to the movie-going experience.
Q: Not true in every case. I saw a IMAX 3D film about Hubble (Hubble in 3D- returning to PacSci soon), and it was so amazing in 3D that I cried (literally). I doubt a 2D film would have elicited that response. But I did not feel it added most other films I've seen in 3D, for example, Megamind.
RE: It's a gimmick created by Hollywood to lure us into theaters and compete with ever better home viewing experiences.
RE: No serious drama could use it well.
Q: Probably not.
I do have a major objection to 3D. And it is NOT that it isn't used well, makes me hurl, and costs more money; all for no story related purpose (most of the time). It is that my eyes readjust more and more quickly with every 3D movie I see.
The first of the new wave of the 3D films I saw was Coraline- and it was 3D the whole time. Nauseating, headache inducing, but excellently utilized, 3D. I watched nearly the entirety of Avatar without my eyes readjusting (though I did get a headache- even with dramamine).
But now, I couldn't get halfway through Megamind without my eyes readjusting. High cost and physical discomfort drive me away from the desire to see anything in 3D. The only reason I see movies in 3D is so that my friends, who obviously don't have as gifted eyes, can go in 3D. And that scarcely seems worth it.
Films that make too much use of 3D, at the expense of better filmaking, look dreadful in 2D; Clash of the Titans, for example. It makes people lazy, and if I pay extra for 3D, I want to see it in 3D. Not in sea-sick, headachey, sloppily made, expensive 2D.