The movie is based on serialized stories from a pulp magazine, of course it's cheesy, but it completely fits the universe they've built. It's very Flash Gordon-esque in its tone and narrative structure, and I was completely fine with that. Outside of Woola, I thought the effects within the film were fantastic. Whether they were worthy of the film's budget is debatable, but I'm hard pressed to come up with many recent films that outdo it in the effects department. The aliens in particular were excellent. The score in John Carter was great and is one of the few thing about the film that isn't polarizing, which isn't surprising considering Michael Giacchino is a fantastic composer.
I did have some issues with the film, mainly it's relatively lean length that I felt could have been expanded to flesh out some of the story tidbits and characters that weren't fleshed out enough. But it was nothing that completely hindered my ability to enjoy the film.
Yes, it was a mindless blockbuster, but that in itself doesn't make it terrible. I'd place it alongside Speed Racer as an enjoyable, yet flawed film, that was incredibly underrated and deserving of more.