Being inspired by something and getting ideas is not ripping it off. By that definition even Akira Toriyama is a rip-off, after all he used several elements of the classic Journey to the West. So no Naruto, Bleach, One Piece and etc. are not rip-offs. If you want to consider something as a rip-off for using the idea the first time then about 99.999% of things are rip-offs.