The Namazu thing was a joke - they changed everyone's avatars to some version of a Namazu for April Fool's.

Anyway, pertaining to the Echo, it's capable of doing much more than the Warrior of Light uses it for. The Ascians and Warriors of Darkness use it to cross dimensions and attain effective immortality, Fordola used it to achieve a combat state akin to Dragon Ball Super's Ultra Instinct, and Zenos used it to possess Shinryu. That said, the Warrior of Light has displayed none of these abilities or expressed the desire to obtain them. As it stands the Warrior of Light is just an exceptionally skilled and talented fighter who happens to be temper-proof - other than persistent superstitions about Echo users, the Eorzean city-states have no reason to fear the Warrior of Light or be jealous of their power. On the contrary, the Warrior of Light is repeatedly entrusted with the fate of nations and various characters (the Scions and GC leaders, f'ex) show guilt and remorse over asking them to shoulder such a heavy burden time and again.