Cameron knows what he is doing. This is his baby and not a creation of someone else. I am not worried. They only thing I'd like to see tighten up with the series is the story. It was a little too "simplistic" in Avatar. It wasn't bad, it just wasn't at the level of Terminator 2 or Aliens. But since he has gotten the setup of the universe and characters out of the way, he is now free to expand the story and go in a different direction and take chances with it. I'm confident he will succeed in every facet from here on out.