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.

This perspective helps a bit with the Foundation trilogy too, honestly. Asimov was not a good character writer.