Avatar is not the first nor the last movie to have a lot of plot holes. It isn't worth taking a fantasy movie and getting overly irritated at all the miniscule little things that weren't quite right.

From my experience with writing and creating visual things for story telling it is important to make things that the viewer can relate and connect to. Sure, the Na'vi were a lot more humanoid than what we would probably find on any other planet, but it enables us to connect and empathize with the race on a visceral level.

Yes, I enjoyed the movie. Sure, it had it's quirks/easter eggs but you will be very hard pressed to find a movie that doesn't.