Very interesting!
...Just thought about it; maybe a completely new character will be introduced. It seems to me like the best tales of awe and wonder happen for the point of view for someone who is experiencing everything for the first time. That's the magic of filmmaking: having you discover something you've already discovered, yet feeling like you haven't seen anything like it before.
...Of course, add new things like the oceans, moons, and what not, but seeing Avatar 2 through the eyes of
another person in awe for the first time sounds really, very exciting. To me, at least.