If it's built, and they do spend $500 million (or even the $750 million at some point for the deluxe version), people will go, find it neat and enjoy themselves. The 99.999% of the visitors to WDW who do not frequent Disney message boards will simply go to DAK, check out the cool theming, attractions, shops or whatever and probably think it's neat. Then, they'll move on.
Why do I think that? Because that's what I do with WWoHP. I very much disliked the one movie I saw, have no interest in seeing the others, but am very appreciative of the theming (except for seeing Duelling Dragons right there), enjoy the scenery, FJ and butterbeer. It's a good time; well done! Then, I leave and never give it another thought. Avatar has so much visual potential, I think it will do well with most everyone except those staunchly opposed to it. Who knows, perhaps even some of them will like the finished product. Ya know, most people just don't take this whole theme park s**t as seriously as some of us on here.