Thanks to bfw182 for his awesome evaluation notes!
Tayuya (Tayuya of the North Gate)
Tayuya is quite a useful character for the correct situation due to the effect of her Ninjutsu.
Firstly she has quite low stats which is a general trend for the long ranged characters as well as not very useful Field and Buddy skills (both reduced slip damage).
Her Ninjutsu has a 2.2 multiplier so she only hits for 1455 but she can quite easily hit all/most enemies with it due to large AOE. This Ninjutsu also has a 40% chance to seal the enemies Ninjutsu for 5 turns which is very handy. The Ninjutsu costs 5 Chakra so is a little expensive especially for low damage.
If you enhance Tayuya with another two copies of herself she also gains some more % chance to seal with her Ninjutsu which is a good ability for her to have.
She is useful for the raids where you need to stop the enemies Ninjutsu but there are other better characters that can cover what she does.