Why did Zhuge Liang's trick finally fail in "Breaking the Dragon" starring Andy Lau and Magic? What's the moral of this?

Zhuge Liang deliberately ignored veteran Zhao Yun when ordering his generals, knowing that Zhao Yun would take the initiative to be good at fighting, and Zhao Yun was the main force considered by the enemy, so when Zhao Yun was surrounded by the enemy, he would only see the words in Zhuge Liang's kit. Zhuge Liang's purpose was to attract Zhao Yun's main force, Zhang Bao and Guan Xing, to attack the enemy city. Personally, I think the overall production of the film is good, and the costume props take into account the background of the times, which has both modern aesthetic feeling and special culture covering the Three Kingdoms period, as well as photography editing and so on. The plot of the film is a little pale, because it is really difficult to perfectly show Zhao Yun's life in 90 minutes. I think the director is familiar with the culture and story background of the Three Kingdoms. You won't pay attention to it, will you? I agree to let Zhuge Liang play with Chen, because Chen will better interpret this confidence. But seeing Zhuge Liang in the dragon armor is not the focus of this play. A * * * only appears twice, and the director will not arrange an actor with a special Zhuge Liang temperament to play it! For example, Zhuge Liang in Red Cliff can be replaced by Chen, which I think will be more to my taste (personal opinion).