Let me clarify. I didn't mean to give the impression that "of Mars" was excised as early s 2008, but that the name had been changed as early as 2008. In a Dec 2011 interview, Stanton addressed it directly:
Originally Posted by flynnibus
"Here’s the real truth of it. I’d already changed it from A Princess Of Mars to John Carter Of Mars. I don’t like to get fixated on it, but I changed Princess Of Mars… because not a single boy would go.
"And then the other truth is, no girl would go to see John Carter Of Mars. So I said, “I don’t won’t to do anything out of fear, I hate doing things out of fear, but I can’t ignore that truth.”
"All the time we were making this big character story which just so happens to be in this big, spectacular new environment. But it’s not about the spectacle, it’s about the investment. I thought, I’ve really worked hard to make all of this an origin story. It’s about a guy becoming John Carter. So I’m not misrepresenting what this movie is, it’s John Carter..."