I'd also venture to say Qin Shi Huang or Cao Cao.

For Shi Huang he basically started the development of the sort-of modern China. Or the state it would assume for a long-ass time. He unified China, ending the Warring States period and set about on a series of grand reforms and projects. He standardized the Empire's measures, enforcing a same systematic method as well as doing the same to the Chinese Language as well as the Imperial currency. He also began the tradition of making government appointments on merit, much less on hereditary right; this continuing on for a long time.

Though he ended an era of free thought in China his reign saw the promotion of the rule of law (it is in face legend written after his reign for future dynasties to distance themselves from his dynasty that he buried hundreds of Confucian scholars alive). On top of this the regionalization of the Empire that saw people identifying themselves as anything but a standard Chinese identity was broken and non-dynastic commanders appointed to rule these areas whose only relevance to the central Empire was their system of alliances and lose pacts. They were then much more centralized and governed as a nation.

All this in the 3rd century BCE. However the Qin dynasty didn't last long because he had probably appointed ministers too sly for his sons' own good, they managing to convince his eldest and his favorite general to commit suicide to put a moron on the throne (Qin Er Shi's rule reads like a comedy).

Cao Cao came a dynasty later at the Twilight of the Han dynasty (you could probably also argue that Emperor Gaozu could be thrown up in here, but I don't got time fo' dat shit).

Of leaders Cao Cao kind of gets a lot of shit mostly because of his rapid success from the son of a foster son of a eunuch to the last Han's Emperor's greatest commanders. He was fierce, but only because he needed to be. Otherwise he was a sharp and quick commander, outside of the Red Cliffs where you could say he was overconfident.

But he was an adept statesman as a councilor of the Han Emperor and later in his own independent kingdom when the Han Empire finally fell apart. And he was said to be very good to his men, so much so they were like his family. He was also a premier poet and in some ways has his own genre of Chinese poetry.

Administratively he focused on his post-Han's state food and education demands, managing to weather a devastating locust plague; the quality of life of both war refugees and his own people increased significantly as a result. He also placed a pretty substantial weight on education in his realm.

However, he died before Chine could be reunified and his sons just sort of petered things out and the advisers took control and then booted the Cao family out.