I think Itachi doesnt have to sacrefice one of his eyes, he has to sacrifice his mouth or his wood-partIsn't this what I have been saying? Izanami is just derived from Talk no Jutsu, of course only Naruto can do it as the main character it won't have any drawbacks on him, but Itachi needs to sacrefice one of his eyes for it.
It decided one's destiny, you just keep on talking and talking until eventually he becomes good AKA destiny changed... It makes the most sense to me this way.