Then here are some more OP skills:

Water Main: Neurotoxin, Acupuncture, Poison Tai, and Healing Tips

Wind Main: Flower Guard, Giant Rasengan being done twice, Shoot Down Rasengan being done twice, Wind Dance, and Dance of Impetus,

Earth Main: Shields galore, immobile, interruption, and Pose of Duel

Lightning Main: Root of the Warrior, Blood Thirsty Demon, ANBU Tactics, Acupuncture, Paralysis, Tag, and Calm Mind

Trust me, every class has something that is OP. It is not just the Fire Main.