I'm really hoping the next three movies shine. The fact that they are all being filmed as one massive project is encouraging. It's starting look like Avatar was the practice run for the franchise. They kept the story simple and proved that the technology, the characters, and the environment all worked together as they should. They got the language, the culture, the materials, etc, all sorted out. We were given the backstory of how Jake wound up on Pandora. Now that all that basic stuff is out of the way, Cameron can make a proper trilogy.
It's going to be weird never seeing Jake in his human form again. I'm also curious as to what his offspring will look like. Will his child(ren) have the same human characteristics that his Avatar possessed?