Weird thread title I know.
When weak martial artists watch master fighters fight, they're always a blur and they don't even know what's happening. But why is this? When you gain super inner strength, your eyes don't suddenly see better or process information faster in your brain. Xu Zhu with 3 billion years of inner strength still could barely see Jiumozhi and got kicked a couple times without even realizing it. So I assume it must be conditioning, where the more you watch people fight, the less blurry they become.
But then how come some people like Wuji can come out and not see everyone else fighting as a blur? He has great inner strength, but he's never seen anyone fight before, nevermind awesome techniques that the elite people he fought with had. He should have seen them blurry, and got stabbed by a sword don't you think?