As much as I know there's some major wank over the ethnicity and races of the actors playing in the movie, the trailer is HOLY SHIT especially when it comes to the Earth and Waterbending portrayed in it. And they seem to be trying to adhere closely to the TV show canon, because the bigass ball of ice that Aang is encased in is pretty close to what's in the movie, and Aang is shown in one brief scene to be escaping the firebenders just like the first time he got captured by Zuko.
So yeah, it might be watchable-ish but maybe not right off in the theaters.
(Why yes, I do feel a bit like I'm going to hell for saying I like the trailer)