It's hard for any sequel to have near as much success as the first because when the overall plot of the whole thing as been seen once it's not as interesting the second or third time around. They would need to provide something different. I guess them being in the water is the "something different" here. The visuals look great but the story I guess would basically be a repeat of the first..? Ill watch it for sure. The first Avatar movie to me was great.
Considering how much success the first one had I can understand taking a chance on this one, even if it's over a decade past the first one. With it apparently being like 3 hours long ill probably wait until I can watch it at home.