I don't want to give the impression it was unalloyed suffering-it wasn't. And I stopped looking at my watch during the battle scenes at the end. But without the 3D, a very ordinary film.
Cold media, normally 'high-resolution', have fewer interpretation possibilities, and are thus usually more 'distant' from the audience. 3D points out that you are a consumer. You can't be me, I'm taken
But, I have found that I'm drawn deeper into films by the experience of 3D. Something to do, I think, with the more "physically" immersive experience. Even though I haven't seen a 3D film yet that's actually all that good.
You get the best kind of writing when there's a scene where no one is saying or doing much, but you know exactly what they're thinking and feeling, what motivates them, and what their plans are.
Cameron is one of the people most responsible for reducing science fiction cinema to comic book narratives, especially from Aliens onwards, which elevated the grunts vs marines trope to the cliche that it's become today, in film and in print.
Compare with 2001, where there was so much showing and so little telling, especially at the end, that a lot of people had no conscious conception of what was happening - but they still had a sense that it was moving and even profound.
But 2001 assumed that audiences were aware enough to follow. Most recent films have left that assumption behind, and assume that audiences are made up of gum chewing fools out for a roller coaster ride and some eye candy.