I have absolutely no desire to see this movie. It looks like a three hour CGI wankfest.
I've actually heard reviewers basically say "When you get past the poor writing and plot, it's great!".
Call me old fashioned, but I actually like a good narrative and well written dialog in my films.
Screw that, IT WAS EPIC. The visuals weren't just CGI wankfest, the animals, the world, and culture of the Naa'vi was outstandingly thorough and original. The plot was predictable, but in the good way that is delivered so well that it feels brilliantly well done. The CGI is merely a means to do the film, which is why it took Cameron a decade to get the technology to make the film he had always wanted to do, unlike say 2012 which was a 2 year development to cash in on conspiracy theories and cgi.
Bottom line: great writing, well constructed plot, outstanding visuals, insane cgi.
tl;dr: don't talk crap, it was amazing.
(oh and FYI, it has 94% cream of the crop on rotten tomatoes, and every film has some detractors, so whoever said what you quoted is just one of those silly idiots).