Guo Jing could have have history and could have made things different for the common people. If he had made different decisions and altered the course in his life.
If he had married the Khan's daughter( and not Huang Rong), he would have become a trusted official in the Khan's court. Because he was such a great General, and the Khan's son-in-law, he had a good chance to inherit the throne. When he becomes the great Khan Guo, he could assimulate the Mongolians into the Han culture. impliment policies that are good for the ordinary people. He could have also united all the Wulin heros and promoted peace and posperity for all.
He would make a good Emperor and Khan of China.