Say what you want about the Avatar film(s), the setting of Pandora is a brilliant choice for a "magical" world brought to life. What I like is that you won't even have to have seen the film or be a fan of it in order to enjoy the land. It reminds me of Cars Land in that regard. Despite the not-so-universal appeal of the film Cars, the land itself is so distinctly 1950s with the music and the neon and the architecture, in addition to being so brilliantly southwestern with the size and scope of the rockwork mountain backdrop, that it immediately speaks to a time and place that grabs you. Like so many things, it's a place that no pictures can do justice - you have to see it in person to feel it. Strolling through that place at night when the neon sparks to life and Sh-boom, Sh-boom plays over the speakers is almost universally effective.
If executed properly (and I believe it will be), Pandora should be equally awe-inspiring, and the cultural impact of the films is independent of all that. Gently glowing flora and fauna, trickling streams and waterways, giant looming mountains hovering above your head, and a lilting orchestral score playing in the background, nobody is going to remember if the movie did or didn't have cultural impact. It's going to be a world of its own. No deep analysis of the film's cultural failings can change that.