Oh hell, I can't resist. Nothing personal, man, but I gotta tackle these "points" you make. I'm feeling snarky.

(None of this is meant as a personal affront. I'm just responding in your same tone... because it's fun)
one of my friends at work convinced me to go to this thing. and pay the $13.00 for it, because you "have" to watch it in 3-D. no you don't! do you really need to see a gun sticking out in your face? do you need the headache you'll get because the 3-D glasses don't match up with your prescription glasses? the answer to both - no.
Umm, I think 3D helped put you in the environment. Of particular note was the briefing session where they cleverly filmed it so it looked like you were sitting right there with soldiers around you. Is it necessary? Nope. Was it kinda cool though? Yep. The 3D glasses work just fine with my 'scripts. The cheesey paper ones don't and cause the issues you've mentioned, but the bulky plastic ones are perfectly fine. I'm just sayin'.
the film opens with a handicapped man having his brother cremated in space. they used a cardboard box for his remains. so we're in the year 2154, and we can't help Marines being paralyzed or use an actual coffin? okay - strike 1.
So, you weren't paying attention at this point. You really shouldn't blame the filmmakers for your lack of attention. They DO have the technology to fix the marine's paralysis, but they're still in a time of capitalistic rule. You can get fixed, if you can afford it. There was no need for a coffin. Ash dispersal in space was his brother's decision. Why the hell would they buy a coffin, or urn in that case? Complete waste of money. Your personal beliefs regarding how the world should work in the future are not a requirement for how a story should be backlit. ;P Strike 1 unstruck.
we then find out the Army is after a rare element known as (and I'm NOT kidding here) UNOBTAINIUM?!? they go the entire film and don't state what this is used for. or why it's only located on this planet. the budget for this was $500 MILLION and you couldn't trademark a name better than unobtainium? okay - strike 2.
Well, for starters, Unobtainium is a scientific term used in the present. Yup, Cameron didn't make it up. Just goes to show exactly how unimaginitive the science community really is. A link for your reading pleasure:
http://www.scifisquad.com/2009/12/23/the-nomenclature-of-avatars-unobtainium/ or if you prefer:
http://en.wikipedia.org/wiki/UnobtainiumIt's use was explained in the movie. It's a room temperature super-conductor with a high magnetic field. You weren't paying attention again, were you? Strike 2 unstruck.
then the pretty colors come in to play. it seems the planet we've shipped out to is called Pandora (again with the stupid tongue in cheek metaphor) and is a hazardous place to be. the natives don't much care for us. but somehow, they've learned English. I'll let that slide, there was a possible scenario for this, but that's being generous. so anyways, we somehow got a sample of the native Na'vi and figured out how to clone empty shells of them. we then take control of these clones, thus the Avatar name. again, we can clone an alien who uses a tail as the ultimate flash drive for interfacing with horses, trees, nature, each other, winged creatures; but we can't fix a spine without billions of dollars? okay - strike 3, you're out, I'm done.
Pandora is a moon, not a planet and it could actually exist. Do a simple search in Google. You'll get thousands of links on the very subject. The natives learned English through the Science team who set up a school in their village using Avatars, and the two species taught one another. Seriously, were you paying attention at all to this movie? We know learning languages is a possibility, even when very disparate in production. Look at the tribal languages of Africa with all the clicks and whistles. Doesn't get much more alien sounding than that, yet they have learned English, French and Deutsch and others have learned their tongue. This event isn't even a reach.
As far as getting the DNA necessary to create the Avatars, again they started out on a peaceful mission on Pandora. This would have been part of the sharing and learning. As for your second attempt to justify your disgust about a paralyzed Marine, see my explanation to Strike one above. It still applies. Strike 3 unstruck.

that literally almost happened, I almost passed out. the first 2 hours of the film will put you to sleep. it's all dialogue, most of it tongue in cheek. and lots of it are unnecessary! yes the Americans wiped out the Indians to the point of near extinction. sad, but it happened. the Nazi's did it to the Jewish people, the English did the same to the Irish, the Romans did the same to the Christians, etc etc etc. bad stuff has happened all throughout history because our species isn't perfect, I get that. but I don't need a 2-hour lecture about it when I'm paying to be entertained by a film. so I don't need the constant comparison nor the guilt trip this movie puts on you.
Here's where your predisposition got in your way. You see, those thoughts didn't occur to anyone I've talked to who has seen the movie. The rest of us saw that as rich character development and environment explanation. Almost no time at all was spent on "humans are destructive RAAAAAH!". That was assumed from the very first briefing which took place around 15 minutes into the movie and wasn't mentioned again until the first attack on the Na'vi.
moving on. the natives want to protect Hometree (argh, another good use of sarcasm there huh) from us invaders.
Ever heard what Native Americans, Tribal Africans, and (since the Na'vi were compared to them, and labeled as such) Aboriginals call places of spiritual importance? It's things like Hometree, Greatoak, Tree of Life. Hell, Christians had an important Burning Bush. Your coughing at nature here. Simpler races use simpler terms. They don't beat around the bush when naming things. It keeps things simple and you know what you're dealing with by it's very name. Beats the hell out of "Maktunkata". That name doesn't tell you it's an active volcano at all...
the "unobtainium" sadly rests below Hometree so you can guess what happens. the lead character is given 3 months to get them to move - or else. in those 3 months, he literally gets the same Dances with Wolves treatment Kevin Costner got, almost to the letter, right down to the marriage. strike 4!
It's close, I'll grant you that. Not EXACT as you claim, but it's close. There was no marriage though, just sex, and it lasted all of one night together.
sure enough, the time runs out so it's time for the military to have their way. Hometree is destroyed, so the natives regroup up at a place called - (again I'm not kidding) Sacred Tree. who's writing this thing again?!? the lead character then gives a speech borrowed from Braveheart, 300, and the Lord of the Rings. again by "borrowed" I mean at the end of his speech, you literally hear the guy stop short of saying "This is SPARTA!" I can't believe I was still sitting there at this point.
Again, I'll refer you to my above point about the names. It is an accurate portrayal. As to your third point, you just named 3 movies which all used the same thing, but those three were somehow OK in doing so, but this one was not? You're having fun with us, right?
As to your first point here, well, didn't I say above it was a typical James Cameron movie? Predictable?
finally, what we've all been waiting 2 hours for. the end fight scene. and it's not completely out of left field, but it's really really stupid. apparently arrows against tanks and bullets can only go so far, so when everybody is about to die, guess what happens? yes the planet has heard their cry for help, and sends the animal populace of the planet against the invaders. you read that right. the animals that were killing the Na'vi earlier on are now sympathetic to their plight and move in to help out. strike 5! sure enough, the animals were the key all along, so the heroes win. the Marines leave dejected, because surely there's no way they wouldn't come back with a hundred times more ordinance. nope, that'd be just silly.
Whoops! Strike 5 missed the mark and proves you weren't paying attention again. The beasts that begin to charge, while assumed to be sent by the spiritual force of the moon by the natives, could have merely been responding to the massive damage to their territorial homes. This happens in nature too. Watch a Rhino or Elephant stampede to protect their territories sometime.
More importantly though, they weren't attacking the Na'vi earlier in the movie. The Na'vi have an understanding and relationship with all creatures in the forest. Those beasts were attacking Avatars earlier in the movie, which everything on that moon can tell is not a tru Na'vi. They smell different and wear different adornments clothes)
While riding the big cat-like beast was a stretch, as the old saying goes, and as does happen in nature, the enemy of my enemy is my friend. Strike 5 unstruck.
in closing. there are so many points taken DIRECTLY from Dances with Wolves, James Cameron better be giving a share of the profits to those people. in fact, if anybody sees James Cameron in real life, tell him he owes me $13.00 and I want it back.
I feel the same way about District 9. I want my money AND my two hours back from the colossal waste that film was. And don;t get me started on Wolverine. It was a decent, enjoyable movie, but they fscked up so much of Wolvies real history it left me pissed. I felt much the same about G.I. Joe and Tranformers (both of them). I keep watching my childhood destroyed, piece by piece, by snot-nosed directors and writers who came into my joys later in life and never bothered to really get to know them before butchering them on screen. I keep waiting for them to destroy Thundercats, It's about the only thing left unscathed.
You're entitled to your opinion. The rest of us are entitled to ours.