Kimono itachi one of the most broken units in the game, but you gotta have some brains the only counter for him is Gaara kazekage sb (properly) and um I guess a kakuzu if a kakuzu can one shot him since his mystery goes threw dodge.

But kimono itachi hard counters the following units:
Madara founder
Konan Taisho
Yamato Anbu
Asuma Wind blade and edo

(Any heavy chakra teams, so Earth main chakra wall, Bani chakra fire main etc got over 51 chakra there your screw'd)

plus any team that requires chakra and let say you can't stop there standard you can increase someone jutsu cooldown from 1 to 3.
so let take edo minato, he hits you with his jutsu now he has to wait 3 rounds, you hit him with kimono itachi mystery now he has to wait 5 rounds.

Plus his kit is pretty nice and plus using him properly kinda is needed