You people are to hasty, she is not dead, and also she hasn't shown everything her secret jutsu is capable of... what the force and a boost in speed? She was already strong, and you can get faster by pumping more chakra. So i doubt that is everything her jutsu does.
You have to remember that with this jutsu she is "immortal" in battle, she can regenerate even organs so just being stabbed by that sword is not enough.
Discuss her strength when she dies, and shows us everything she has, only then you can truly call her a weak and disappointing character.