I don't think Kakashi surpasses Itachi in any real area of being a ninja. Itachi is better at taijutsu, genjutsu, and ninjutsu execution, and katons are better than raitons for ninja without exceptional defenses, because katons cover a much larger area while raitons focus on piercing through jutsu defenses (Kakashi has none, nor does Itachi with restrictions.)
Kakashi kept up with Itachi when he said Itachi was holding back (part I) and when he said Itachi was clearly stalling in part II, not to mention Itachi was only at 30%, and said that his strength and not just his jutsu pool were proportional to that, which we know is the case with clones in general...
So there really isn't an argument for Kakashi going toe to toe with Itachi in these fields.