Plot and story are very important. To me the most enjoyable movie of the year is usually the best script winner. Almost never the best movie winner.

But there's this thing called cinematography. And when it is done well, it adds another layer of enjoyment to the movie viewing experience. 3D is part of cinematography.

So, yes, plot is important. But if you are watching a movie instead of just reading a book, it is usually because the added elements are worth it.

And I say that as someone who usually reads the books as well.

3D is fun, and films like Avatar and Tron and Pacific Rim are totally worth in 3D.