I just went ??? at the idea of Wei Wuxian being dense. He's very much not, I mean, he's a master at deduction, socially he's very skilled, he has leader abilities, and a whole lot of empathy, too! (Preaching to the choir, I know.) It's just that everybody has blind spots, and especially smart people might tend to believe that their reasoning is sound even when it's not, for once - because they're usually right ;)