This is Dances with Wolves in Sci Fi, perhaps one of the most creative 'effects' films ever made. Cameron crafted an entire eco-system (hundreds of species, with common genetic links). It will go down as one of the finest science fiction films of the decade (perhaps like Jurassic Park).
There is some mild swearing, but even my 6 year old knows those never get used by children. The 'native' bodies are partially clad, but nothing is made of that - in fact the effect would be to normalize bodies rather than have them be objects of titillation - a very good thing.
There are two early scenes with native animals that are immensely scary, and some military style violence that had an emotional effect on my son.
On the other hand, violence comes out very badly (as does the military, as do corporations). While there is plenty of violence, violence is not revered (as perhaps in Rambo style movies or GI Joe or the like), but rather to be deplored.
However the imagery is intense - and certain under 8 year olds might be disturbed.