Yeah if she had just killed Saurfang and said some kind of pro Horde statement and maybe even made some kind of appeal to the rebels she would probably still be Warchief. They were terrible at showing it but if she is able to make the majority of the Horde turn on their leaders, including Thrall himself, then she should have been able to keep her spot and continue her little plan. Hell, it would have made everything else she did even easier. Beating Bolvar, capturing Anduin,etc.