DBZ is overrated. End of story. I actually had to login to comment on this. As for DBZ influencing Yu Yu Hakusho, their original mangas were released quite close to each other, but it's just the DBZ anime got over here first. Another thing is whereas the fighting for Yu Yu and everything was planned from the beginning, DBZ was not, so yeah while you can say it influenced Naruto, One Piece, Fairy Tail, and etc.., I don't believe it influenced Yu Yu.