this is no coincidence if you ask me. Avatar is only being compared to pocahontas now because the teenage age group of today finds it to be a very similar story. Avatar is WAY more similar to dances with wolves; it differs slightly from Pocahontas in a few ways. the theme and emotion of the two movies is nearly identical
and also, think about it... James Cameron supposedly writes a perfect script which only has to wait for technology to catch up, 15 years ago... go back another 5 years and dances with wolves wins it big at the Oscars. I don't see a chance of their not being a coincidence. I think he really did rip off DWW knowingly.