Except the 'dark crystal' seen in that Echo vision is basically a pallette swap of Hydaelyn Herself, which is why players naturally assumed it's Zodiark, who is technically Hydaelyn's literal dark counterpart. Of course the Chysalis shows something different, but the jury is still out on exactly what that Echo scene after the end credits was (a thing to remember is the Echo only views the past by reading another's memories - if can't send someone into the future because the future hasn't been written yet).