As I re-read and think more about Huan Wen's story, the more it's really grown on me. He's very lost and conflicted, and it's not clear to him what the right path is. As an introspective and inward-turning person who has held himself aloof or at a distance even from his friends, it's especially hard to express and open up. On paper it might seem cliche, but the way it's portrayed feels very real.
Compared to the vibrant university environment at beginning of the story, the arcs have steadily shifted to a slightly more "adult" tone. Or put another way, the tone since the uncle Pan arc particularly feels more "lonely", that doesn't have an absolute guarantee of an ideal "happy ending" like with Yu Yang and Li Huan. Sometimes, like Pan and Huan Wen, we are faced with the possibility that the loneliness will last a long time, living day to day as adults. It's hard to describe exactly, but that subtle transition is really well done.