The original Avatar was a new and unique story line, a bit like the original Star Wars. A 2nd movie was always going to loose that uniqueness. However the story has to be told to join episode 1 to 3, and The way of water has done this. I felt like I ran out of steam after 2 hours 30, but there was so much that needed to be told that I understand why it was so long.
Well worth the watch, looking forward to 3 4 & 5