Decent movie on its own (loses points for highly uneven pacing, Disneyfication) , but a lousy adaptation, at best. They destroyed Sola's character. They were just barely on this side of turning Tars Tarkas into Jar Jar Binks. The Tharks weren't sufficiently Thark-y (though perhaps I shouldn't be surprised, give that this is a Disney flick), lacking the casual cruelty, lack of emotions, and formality that marked them in the book. The red men weren't red enough, and the whole setting seemed far too familiar... not alien enough. The Heliumites were your standard sword-and-sandles-with-tech trope. Princess Leia was a better Dejah Thoris than Dejah Thoris, who could have been pulled from any romantic comedy where the at-least-outwardly-strong female lead gets married in the end. I pictured a cross between Princess Leia and Anck-Sun-Amun, not what the movie delivered. I won't comment on the Therns because they're in the next book, which I'm only partway through, but I did notice that their writing was mid-to-late cuneiform, or very similar.
It's funny because I read them the other way around, but the deal with the Gods of Mars and the Therns is a theme Norman borrowed heavily from in his GOR books. As for your other points, yeah. The strength and nobility of the Red race failed to shine through in this movie, especially with powerhouse actors like Hinds, West, and Purefoy in there. It could have been...glorious.
Finished book one in four days - that has to be a record for me. No wait, I read a Spenser mystery in one sitting once.
Just saw it last night, and while I have some nits to pick here and there, overall, I liked it. In my group, it seemed that those who'd read the books enjoyed it, if they hadn't, not so much.
Saw it with my younger son last night. Really enjoyed it. Thought the acting was decent, the story was good, the effects were tremendous. Of course, I haven't read the books. But I was pleased and did not feel like I'd wasted my time or $. I would recommend it. Hell, I even thought the Mrs. would've liked it, which says something.