It would be wise not to make the other sequels unless James Cameron directs them. I believe fans should ask James if he always planned to do 3. If so, then thats great. If not, they should not be made. keep it sacred.
I just saw Avatar 3D and it really blew my mind. I was so impressed with the subtle 3d effects. Even the story kept along well during the whole 3 hours. The movie didnt feel long at all! thats a first for me!. James Cameron is such a unique director I hope we can make him an Avatar in the future.