I had heard the D23 convention footage was amazing. This trailer shows less than that footage did, but I agree that the film looks ridiculously good. Nothing in this movie was filmed on location. All of the jungle and river is CGI which is pretty damned impressive.
I've watched the trailer a few times now and the thing that kept sticking out to me was Scarlett's voice as Kaa. It just seemed too kind and gentle. I know that that's what they want the snake to be, something cunning and comforting for Mowgli to lure him in. I just felt like the comforting side seemed a little too heavy from this little clip.