The Han Empire was the result of a civil war that came out of the collapse of the Qin Empire. It was founded, interestingly enough, by a peasant. This particular peasant retained much of the Qin legalist system but modified the worst excesses, and again used the Mandate of Heaven concept to justify how a Peasant could claim to be the universal Son of Heaven. The Han Empire established a fairly formidable military system, under Wudi it actually conquered more under one single Emperor than the entirety of the Roman Republic and Roman Empires put together.
The major weaknesses of the Former Han proved to be the very clan-based structure of Chinese politics that influenced the imperial system, namely the promotion of favorites of powerful women for no other reason other than being someone's cousin/uncle/nephew/son without regard for actual competence. Too, the emergence of the eunuchs during this time meant that the Court could be divided into multiple feuding factions, all of whom would find it preferable to have a minor Son of Heaven on the throne who would not be able to contain them any at all.
Zhonghua/All Under Heaven basically at this point is a Rome without a Parthia near it, it was not very open to foreign ideas because it had no nearby sophisticated competitors to challenge its own. Confucianism at this point in time is a more narrowly limited philosophy than later Confucianism, while the Chinese system as a whole in the Former Han started very centralized but enough minor emperors and noble intrigue helped pave the way for ultimately Wang Mang's coup.