The nerf will absolutely crush him and his usefulness, turning him into just another damage dealer like Sasuke or Kakashi. But he'll be squishy defensively and prone to getting autoed so he won't be in the front lines anymore starting your combos.

If you're just looking for the Fire-version of Random DPS Ninja X then you might keep him around. But if you like his revive and his front style gameplay, go with the ninja that isn't getting nerfed and remains one of the best Arena healers.