Second, by the time Sima Yi commanded a large field army, Cao Cao had died for a long time. Sima Yi represented powerful large land-owners who would gain monopoly on official positions during Cao Pi's reign, Cao Cao's son. It is a recipe for weakening imperial authority and endangering emperors. Historians argue that Cao Cao passed up the chance to become emperor because he would not countenance such policy.
Third, that TV show is like so much of Chinese TV that is a wasteland. It is melodramatic, ludicrous, and laughably bad acting. I am sorry, but it is unwatchable, not just the show, even the trailer. Compare the stylized combat and bloodletting to the realism of "Game of Throne" (yes, I am ware of the irony of calling historical drama fake and fantasy real); there is no comparison. Nothing there is believable, much like every word out of CCP's mouth. It is sad, really.
On the other hand, GoT does the same sort of thing in reverse; technical polish and a realistic aesthetic are the vehicle for a different set of propositions about how the world works. One genre uses fantastical formalism while another relies on fantastical plots.
It's interesting to contrast these two with more subversive explorations of the same forms, like Shadow and Watchmen (the movie; I haven't seen the TV reimagining yet though people seem to be raving about it).
The show's main character is SiMa Yi, which is kind of new to me. It's like a retold of "Romance of Three Kingdom" from a SiMa family and Cao family perspective. Though I hated a lot of Chinese TV shows, this one I actually like and would recommend. I can't remember any combat in this show though, probably fairly average. I wouldn't compare it to Game of Thrones, maybe House of Cards is a closer genre.
PS: And yes, good catch. Cao cao actually wasn't emperor officially. His son became emperor. Totally forgot that point for some reason.
"A dead Zhuge scares away a living Zhongda (Sima Yi)."
https://en.wikipedia.org/wiki/Battle_of_Wuzhang_Plains
Then of course there's the gathering of arrows, but there are too many good stories to talk about. Just look in one of my brocade sacks, each has a useful story! (Chapter 54)
Cao Cao volunteered for assassination mission but asked Wang Yun for a renowned sword/knife as the assassination weapon. As he entered Dong Zhou's chamber he encountered general Lu Bu, a fearsome warrior and Dong Zhou's personal body guard. Cao Cao told Lu Bu that he wanted to try out a famously fast horse of Dong Zhou and asked the general to fetch it. When Cao Cao failed to kill Dong Zhou, he pretended that he was gifting the famous (assassination weapon) sword as a token of respect. Then he went outside and jumped on the famously swift horse general Lu Bu just brought at Cao Cao's request and fled, while Dong Zhou and Lu Bu were puzzled by Cao Cao's action.
I cannot vouch for the story's authenticity, but what a fascinating story.
Also the story becomes more deep when you realize that there are story elements where they act like the character would coincidentally slip into a situation but actually was probably stupid on purpose to create a much better outcome for himself. My favorite example being when Caocao fails to kill Dong Zhuo who is laying in front of him sleeping. If you are a mass murderer like either of these two there is almost no chance to fail to assassinate someone laying in front of you sleeping. And yet Caocao did.
What happened due to this failure? The rebels took him in and started to listen to his ideas, when before they ignored him due to his low background. Also one of his biggest competitors, Wang Yun, who coincidentally is the owner of the knife used in the attempted murder.
What would have happened if he had successfully killed Dong Zhuo? Lu Bu probably would have killed him on the spot. Maybe he would go in history as a small hero but he would have never become emperor.