She has 2 weaknesses. First one being 60 chakra cost, alone she can't do anything till turn 3, so you have to use chakra generator on your team. Second is she is one of more fragile ninjas with little utility.

She is not even that strong over all, it's self evident as no other mains but water use her. If we compare her to something like Sage Naruto who is used a lot with Fire/Wind/Water and who also does more damage then 1010 if he has same amount of buffs and can start combo and stand on move 1 because he isn't made out of paper.

She might appear op to you but really can you name me one other team apart from Mei/Mabui/Water where she don't perform below average and will get rolled by all other meta teams.