I love the blatant and annoying denials in this thread. It's a fact that bar the Edos - who are obviously dead and have no means of stopping IT, making them potentially just as useless as the rest - Sasuke is the only individual who is the key to stopping IT. Even Black Zetsu agrees, who is basically Kaguya's will. You deny this, you deny the important plot factor.
Let's not also forget that Naruto may have a messiah-complex going for him, but the fact that he seeks recognition from everyone dampens his character, making him supremely puerile and redundant in every sense of the world. A Savouir wouldn't seek validation, he would bring about realization through his actions. Sasuke fits the bill far more than Naruto here.
IT has enslaved the world, and the Liberator, the one who can end the " Grand Illusion " would be the True Saviour. It's just a fact at this point. Limiting this factor to the manga's title is petty and nonsensical and is a deterrent to the understanding of the entire concept. Face it, if this is the logic most Naruto fans bring, then their pettiness and lack of comprehension knows no bounds. Not that it's any surprising, given their track record.
So yes, I completely agree with OP. As that's the way the premise is. Without Sasuke's eye there is no way out of it. What's even more interesting is that the Sage granted Sasuke Kaguya's eye to end the enslavement of Humanity, and not Naruto. He must have known that his mother would intervene sooner or later. So to match her power, Sasuke was given the eye to battle her. This time, the favoritism was heavier for Indra's line. It gives Sasuke that much more mettle to win this battle.
Sounds like an all-round Saviour to me.