Try to read this as Chinese literature and not apply Western standards. TBP is not about individual people but civilizations. Similarly, if you read Tale of Genji expecting a plot, you will be disappointed. But that doesn't mean it will be forgotten in 10 years.
Yep. Individual character development isn't Liu's strongest suit. His characters are mostly just allegories to prove a point. (Wenje - bitterness, Luo Ji - logic, etc.) But Liu is brilliant in his deception of mass psychology--the various ways in which large groups react to hopelessness.
Interestingly, I see a lot of parallels between Liu and Thomas Hardy. They both wrote sweeping tales that use individuals to represent abstract ideas. So, it's not just an Eastern thing.
Try to read this as Chinese literature and not apply Western standards. TBP is not about individual people but civilizations. Similarly, if you read Tale of Genji expecting a plot, you will be disappointed. But that doesn't mean it will be forgotten in 10 years.