Hatake Kakashi, good theory... about what's going to happen in the next chapters.
Itachi Uchiha is godlike, FACT, non can beat mange-sharingan, maybe if they find a hidden scroll from ancient times that describe how to counter it ^^. I see itachi most like a genjutsu user, it's impossible to beat him in genjutsu (illusionary) and his speed is like Hiko's speed in RK, (just to compare with other anime)