It's rough around the edges, but it gives you a better sense of the film.
I remain embargoed about John Carter, but I think it's ok for me to say that the marketing on the movie has been BAD. Disney has simply been releasing ads and trailers that seem intended to discourage interest in the movie; they're bland and not fun.
This trailer is fanmade, and it's using elements available from previous trailers, ads and featurettes. The editing is a little rough, but I think that the flow of this trailer - especially the way it lays out the basics of the story - make it head and shoulders above everything Disney has put out.
Is it too late to put 'Of Mars' back on this movie?