Liu Cixin is a bad author, in all regards. Still, the Asimov comparison holds water in that Asimov never could write a character anyone cares about either. He does seem to be more self-aware of it than Cixin is though. Cixin actually tries to write personalities, whereas Asimov bypasses them. Clarke bypasses them. Very unfortunately, late Stephenson largely falls into the same pattern, despite standing quite a bit above the rest. Though Stephenson obviously built on the foundation (hue) Asimov and Clarke established, so it's not fully fair to compare them.
In short, these books are bad. Cixin is closer to NK Jemisin than other Nebula Award winners.
Could just be me, but I only remember the full context of the cannibal leader char in Seveneves. I could tell you some abstraction of "There was that programmer woman from the miner magnate family and there was that one guy that was hanging out with the eves", but it's all pretty blurry. I don't remember anyone from Anathem. My main issue is that I can't even tell you who the main character of Seveneves was, if there was one. I remember that there was one in Anathem, but could I tell you anything about him? Nope, just good sci fi. I remember everyone from Snow Crash, and I definitely remember the main char from Diamond Age, her dad, the guy he robbed, etc.
Seveneves? Great scenario and ideas, but I couldn't care less about any of the characters, and I probably don't remember any.
Still enjoyed the read a lot though.
In short, these books are bad. Cixin is closer to NK Jemisin than other Nebula Award winners.