While some people might say Michelle Rhee had a bad year — having to step down from her job as chancellor of the D.C. public school system — her exit leaves her more room to move and accomplish her goals. She entered that job as a disliked underdog and left it a rock star. Trying to turn around the D.C. school system is like trying to steer a tanker with sailors aboard who are almost on the board of mutiny. Many thought she was Captain Bligh, for her hard-nosed style, or maybe the obsessive Captain Ahab. So, instead of leaving her post because of fatigue or failure, she left just weeks after the release of the documentary “Waiting for Superman,” which painted her as a hero under siege. She was and still is the toast of the talk show circuit. And now, no longer bound by the rules and politics of a city, she set up her own organization called Students First. Her goal is to reform the U.S. school system.