It's no secret that Lord of the Rings: Return of the King cut a lot of content, but it was a blessing that one particular scene was removed. Behind-the-scenes outtakes from Return of the King (via Youtube) featured director Peter Jackson and Aragorn actor Viggo Mortensen discussing a final battle between Aragorn and Sauron in his physical form, which was ultimately cut. The scene would've taken place during the ultimate clash between the heroes and Sauron's forces outside of Mordor. The original scene initially saw Sauron appear in his angelic form, Annatar, blinding Gandalf, Aragorn, and the other heroes. He then transformed into his physical body as seen in the prologue of The Fellowship of the Ring, though Jackson emphasized that this time he was to appear even larger.
The final cut of the film featured no such scene. Instead, it focused on Frodo and Sam's journey to drop the one ring into the lava of Mount Doom, destroying it once and for all. Aragorn did have a confrontation with The Mouth of Sauron, a monstrous emissary of the dark lord, though this scene only appeared in the film's extended edition. In all versions, Aragorn fought alongside the rest of the forces of good against Sauron's army, and notably took on a mighty troll on his own. By comparison, Sauron was relegated to his demonic eye form, watching over the battle from the top of Mount Doom.
Had the Sauron fight scene remained in Return of the King, the film would've undoubtedly been a weaker conclusion to one of the most famous and beloved trilogies of all time. Sauron's presence was felt continuously throughout the films. From his all-seeing eye to his creepy voice within a palantír, he was always there. Having a tall man in an over-the-top costume would've only served to diminish the tension of the scene and reduce Sauron to yet another monster for Aragorn to slay. By keeping him as a presence, rather than a man, Tolkien and Jackson emphasized his status as a being beyond human understanding and one that was too powerful to fight his own battles.
Some have also criticized Sauron's costume during the pre-credits scene of Fellowship of the Ring and suggested that it looked a little overcomplicated and silly. The suit was somewhat over-designed when compared to the iconic and terrifying visages of the Mouth of Sauron, the Witch-King, and the Ringwraiths. Unfortunately, the behind-the-scenes footage for Return of the King didn't make the lord of darkness look much better. Granted, this was early footage before editing and color grading, but the suit still looked jarringly silly. Seeing Aragorn do battle with this version of Sauron would've been pretty distracting. Additionally, the introduction of his Annatar form could've been even more confusing, as viewers may not have understood why he looked different from his appearance in Fellowship of the Ring.
Jackson himself admitted that the final battle would've been far less impactful had Sauron made a physical appearance. The encounter wasn't present in the book, so it was entirely made up by Jackson for the film. The director went on to say that he felt that Sauron's presence was ultimately unnecessary and actually detracted from what the scene should've been about; Aragorn buying time for Frodo and Sam so that they had a better chance to destroy the ring. Fortunately, the scene didn't go to waste as the director was able to turn Aragorn's fight into a battle with a troll, which was a far more appropriate and less distracting final adversary.
It was partly because Jackson cared so much about staying true to Tolkien's vision that he understood the need to cut this scene. The culmination of The Lord of the Rings' story was always meant to be Frodo and Sam's journey, and though Aragorn was certainly a major protagonist, a final battle against Sauron simply wasn't necessary. Return of the King worked perfectly without it, and Sauron still felt like a major threat despite his lack of a physical form. Jackson knew that the fight would hinder, not help the film, and it was all the better for its removal.