John Carter is a good film. Is it a great film? Compared to Citizen Kane and The Dark Knight I've seen better, but it wasn't bad by any stretch of the imagination. On the Disney scale I would say that it was their best live-action film since the first Pirates of the Caribbean, and as Scientific Romances go it was their best since 20,000 Leagues Under the Sea. As someone who has read the books and loves the genre enough to write a blog about it, I thoroughly enjoyed the film. My girlfriend - who loves Disney's fairy tales and has never heard of A Princess of Mars before - also quite enjoyed it. Personally I'm not sure what anyone who says it was a bad film was smoking when they saw it, and I was amused that at least half of the negative reviews I read were from people who didn't like the genre (my favourite complained that it was just like a dusty old sword-and-sandal epic... um, that's a good thing).
No, this fiasco dirties the hands of marketeers who couldn't figure out to mention in trailers that it was from the director of Wall-E, the creator of Tarzan and written by a Pulitzer Prize-winning novelist, or that maybe they should make some toys for it, or do some promotion in Tomorrowland.