Dang it Bob, you almost made me lose an entire afternoon on Tropes! That has happened too many times to me before already!
Also, I found interesting parallels between Avatar and one of my all-time favorite movies, The Last Samurai. (In no way trying to say there was any ripping off, just about everything needs justification and clarification these days.)
hmm Bob, I see you ended your story with the CivBecomesJadedArc004 trope.
ALSO!!11ALIENS DONT TALK ENGLISH!!111OMG
Overall, people use Tropes as a new reason to feel superior to others (for some reason, jaded = superior). Very easy way out if you want to be dismissive towards something.
It all seems to tie together with the idea of "originality" held to such a high standard in north american culture. There is nothing wrong with originality, but in NA it is seen as the end goal of a work. Invent something new and you are rich/famous/successful etc. It disregards the need for actual craftsmanship and skill, as well as the need to understand what came before you and why it worked or not.
I like to compare this to the journey an artist/craftsman would do in the middle ages: First you are an apprentice, you learn the basic trade. Then you are a journeyman, you go around and learn the trade of a bunch of masters. Then you do your big "graduation" piece, which must show that you mastered the trade of those before you. After which (if you are not already dead from all the middle ages stuff) you start to show originality in your own work, improving stuff, etc.
Not necessarily the ideal arc for an artist, but, i would argue, better than the discovered medium -> do something original approach a lot of people take.
Not being original doesnt mean one's work has no value. If it is well done, AND original, even better, but a very well done re-telling of an old story is a very difficult and rewarding thing to do.