This is really strange. I didn't even think for a second that it may be dimmer than ususal.
What I heard is that there are different methods of projecting and viewing in different theaters. Oshyan, you said you were in an Imax theater. I read about some people who saw Avatar in Imax theaters and in regular 3D cinemas as well.
Some reported that the effect was a lot better in regular theaters.
I don't understand why a lot of people think that 3D is only good for some non realistic movies. In my opinion
every movie could benefit from the third dimension. Imagine documentary films. Wide shots, nature... I have seen some small (crosseyed stereo) films on youtube, one of them is a travelogue of a journey to Italy. The third dimension adds a lot to the feeling of being there (OK, I agree, when you're watching a film more than three minutes with your eyes crossed, you GET a headache!
).
After we had seen Avatar, my wife was really blown away from the 3D-effect. But she also said that this may be something for action movies or scifi movies. But I told her why not a Jane Austen movie in 3D? (SHE likes Jane Austen movies.
SHE! ) I could imagine the depth would perfectly enhance the (admittedly) beautiful landscapes and also the interior shots.
All in all I think most of the arguments against 3D are the result of technical inadequacies. Luckily I didn't realise any of them. But I hope that there will be a further development in 3D.