Some characters give off the impression that they are weaker or stronger than they are, because of JY descriptions, or because they had impressive entrances and not forced to fght Greats that can humiliate them, or vice versa. Which characters do you feel are always thought of to be much stronger/weaker than they are?
For me, Xie Xun has always ranked to be incredibly strong and I can't imagine anyone really humiliating and beating him in a fight. He has an incredible Hulk feel, in that the angrier he gets the stronger he gets. But we all know that's not true. Kongjian toyed with him, he was blinded by a low leve Yin susu, he's no match for Cheng Kun before and after 30 or so years, and he himself is of course only equal to Granny Gold Flower and the rest of the people in her range. Still, for some reason I'll probably take him over most characters in other novels that aren't ranked specifically if we're trying to compare how strong they are.
Conversely, I think someone like Yin Liiting or Kong Wen Divine Monk is weaker than they actually are. Yin, especially after Wuji has grown up, is probably very close to the Ming Sect guardians, but it wouldn't surprise me no matter who defeated him. Kong Wen should be on an even higher level than someone like Yang Xiao, but I wouldn't even think of him when top fighters of HSDS are mentioned.