1) “From the start, much is made of Jake’s lack of intelligence. He is an empty vessel, and the question is how much new knowledge will he retain, as his life will depend on it.”

Towards the final battle, Jack was explaining battlefield tactics to the Na’vi. He seemed to understand it quite well, which puts him much higher than just a dumb grunt.

2) “But it is a wonder why evangelical Christians aren’t up in arms over the movie’s spiritual component.”

I take it that mainstream evangelicals don’t have a major beef with New Agers. They seem much more threatened by secularism. In a fight between a secular group verses a bunch spiritual New Agers (or even Muslims or Jews), an evangelical would root for the New Agers any day. They’d probably see it as a victory for spiritualism.

“The humans express no religion at all, except perhaps in cursing (which like sex adds realism, don’t you know). The Na’vi are fervent in a made-for-Avatar animism-slash-Buddhism,”

Normally this would be seen as offensive, except for the fact that it was the humans that were the bad guys in this movie, not the Na’vi. The secularist were portrayed as the brutal savages, and the losers of the war. Since evangelicals are always complaining how Hollywood portrays religion, this would be a huge improvement (even if its not their religion).