On this forum, people have suggested an alternate end to the Warring States Period, with a few supporting the concept of Chu unifying (or reunifying depending on how one looks at it) China, which isn't impossible. However, I don't think anybody looked at what would happen if the state of Zhao, which was Qin's stronger rival, had united China. I found a possible POD with the 260 BCE Battle of Changping, where Qin won and Zhao lost. What do you think would have happened in the long run if Qin lost this battle? Would it lead to Zhao unifying China, or might the entire Chinese imperial system be butterflied away?