Looking at the "Romance of the Three Kingdoms", Jiang Wei was not demeaned, but elevated him. At the end of the "Biography of Jiang Wei in the Chronicle of the Three Kingdoms", the evaluation of Jiang Wei is:
Jiang Wei has a rough culture and martial arts, and is determined to make a meritorious name, while playing with the crowd brigade, the ming is not careful, and eventually leads to death. Lao Tzu has clouds: "Those who rule a big country cook small fresh." "What about the mere ferventures, and can it be disturbed repeatedly?"

This evaluation is an objective evaluation of Jiang Wei. In the "Romance of the Three Kingdoms", the combined transmission of Jiang Wei with Jiang Wan and Fei Yi also believes that Jiang Wei is the embodiment of inheriting Zhuge Liang's legacy.
Saying that Jiang Wei is rough and literate is an accepted evaluation by everyone. When Zhuge Liang was alive, Jiang Wei was once praised by Zhuge Liang. However, we can look at Zhuge Liang's positioning of him, "Jiang Boyo is loyal to current affairs, thinks precisely, and considers everything he has, and Yongnan and Ji Chang are not as good as they are." Its man, Sergeant Liangzhou also. "It just positioned him above Li Shao and Ma Liang, and didn't regard him as a particularly outstanding talent."
As for the evaluation of the personnel within the Shu Han Dynasty, Fei Yi said of Wei Yue: "We are not as good as The Minister of The Xiang is far away; the Minister of The Chu is still unable to determine the Middle Summer, and the situation is that I am waiting!" It is better to protect the country and govern the people, to respect the community, and to do so, so that those who are able to do so cannot hope to succeed or fail in one fell swoop. If you are not as good as you want, you will not be able to regret it. ”
Zhong Hui's evaluation of Jiang Wei was, "With BoJobi middle-earth celebrities, public rest, Taichu can not win." That is, at the level of Xiahou Xuan and Xiahou Sheng.
And Deng Ai's evaluation is even more harsh, he said, "Jiang Wei has been a male child since the time, and he is worth a certain time, so he is poor." The implication is that Jiang Wei is not his opponent at all.
Judging from the internal and external evaluations at that time, the evaluation of Jiang Wei was not very high, believing that he could not achieve the will of the Success of the Northern Expedition. However, jiang Wei ignored everyone's opposition and repeatedly carried out the Northern Expedition, and finally the people were exhausted.
If we judge Jiang Wei's Northern Expedition, we can see that Jiang Wei's actions have no clear strategic intentions, and there is no corresponding clear action in tactics. His Northern Expedition was actually similar to military harassment. However, there is no need to send out national troops to carry out military harassment, which creates an inversion of the horse.
Unlike Zhuge Liang, Jiang Wei only took care of the military, and he paid no attention to the country's economy and politics. During Zhuge Liang's Northern Expedition, it was a coordinated economic arrangement for the whole country, and it took a period of savings before military operations began.
Jiang Wei, on the other hand, didn't ask any questions, just went to war at will. During his military campaign, he depleted the accumulation of Jiang Huan and Fei Yi over the years, leaving the entire Shu Han Dynasty on the verge of economic collapse and political demise.
Moreover, Jiang Wei also arbitrarily commanded, arbitrarily changing the effective defense policy, destroying the defense system of Hanzhong and opening the door to steal, so that Zhong Hui could easily take Hanzhong. In order to remedy this, Jiang Wei was forced to retreat to the Sword Pavilion. Jiang Wei's main force was thus restrained by Zhong Hui, so that Zhong Hui was able to sneak across Yinping to the city of Chengdu and force Liu Chan to land.
If it were not for Jiang Wei's careless change of Hanzhong's defense system, relying on Qinling Tianwei to drag Zhong Hui down. Even if Deng Ai had ten guts, he wouldn't dare to smuggle yin ping. Because Zhong would be held back by the dangerous terrain, Jiang Wei's troops could be transferred to dangerous places at any time to remedy. Deng Ai will never seek his own death.
Therefore, we can see that Jiang Wei was actually the culprit who destroyed the Shu Han. And the evaluation of him in the "Romance of the Three Kingdoms" is no longer extremely demeaning, but quite elevated him.