It's funny that Cameron is only going to make Avatar films because for the past 25 years, he's been making the same film over and over again (with a few exceptions like Titanic). I recently watched The Abyss and was cracking up over how he uses the SAME CHARACTERS OVER AND OVER AND OVER AGAIN. Aliens, The Abyss, Avatar, they're all pretty much the same goddamned film.
I'm not saying they're bad films when viewed independently (well, mostly The Abyss or Aliens) but as a whole, they show just how limited Cameron's scope of imagination can be. James Cameron always has and always will be a poor imitation of George Lucas, even when you factor in how Lucas has slowly gone insane over the past 20 years.
PS. Avatar was a mix of mediocre and terrible. I cannot express how much I do not care about the sequel.