It's not so much John Carter was a bad movie, just a severely misguided movie. Stanton isn't disciplined in live-action filmmaking which is really what screwed him up. Way too much of the budget went toward frequent reshoots that skyrocketed the budget. Had Stanton worked elsewhere, something like Brad Bird did with the most recent Mission: Impossible, he could have done something great. John Carter wasn't the film to kick start his live-action directing career, if he even ends up having one.
And yes, to answer your questions: from my understanding, Rich Ross was the one who was set on getting the Muppets made by 2011.