
And so Middle Earth would have fallen into a new Age of Darkness. In the books, it isn't just Rohan under assault from the titular two towers of Orthanc and Barad-dr, but Lothlrien. Peter Jackson's reasoning for adding the elves to the climactic Helm's Deep battle is addressed on the commentary track for The Lord of the Rings: The Two Towers. Sauron would not have been distracted by Gondor's army at the Black Gates, Frodo would inevitably have been caught and the Ring returned to its Master. Related: Why The Lord Of The Rings Is Actually 6 Books, Not 3. Gondor would have stood alone, Minas Tirith would have been sacked, and so first Gondor and then Rohan would have fallen. The highlight of that part is, while Legolas and Aragorn are punching and tripping the guards, Gimli seems to be just ramming headfirst into.

Theres the scene with Gandalf walking calmly and confidently up to Théoden, ignoring the chaos as Aragorn, Legolas, and Gimli bat guards out of the way in the background. The Rohirrim could not have come to their aid, and Aragorn had not yet called the Dead to honour their oath. Also a meta example Peter Jackson was fully aware of the Anachronism Stew. And more, if Sauron had somehow managed to find out so soon that Aragorn was the living heir of Isildur, he would have had no choice but to launch his planned assault on Gondor immediately, which would have caught the men of the West off guard long before they were prepared.

If Aragorn has been hidden all his life, and never revealed himself in the Orthanc stone, then how can Sauron know of his existence? There's nobody who could have told him, because the only one who might have was Saruman, who wanted the Ring for himself. This deviation in the film creates a major plot hole.

In the books he only reveals himself to Sauron by using Saruman's palantír to wrestle with Sauron, and that only the night before he sets off through the Paths of the Dead. But Aragorn had spent his entire life hiding from Sauron, even concealing his own identity to stay safe and hidden from Sauron. In Fangorn forest, Gandalf tells Aragorn that Sauron fears him, fears what he may become.
