Kaji is not "too good" at all. He even fails at the basic things that he knows he shouldn't. Like for example not letting your emotional state of mind show during a game. A mistake that totally makes sense given how new he is to this; but he's also now aware after a number of similar ordeals of the things that he has to pay attention too, and so he does. He's nowhere near the top players, but far above what an average person would be like, which is a realistic transition.