Star Wars: Rogue One - 9 Ways It Actually Improves The Original Trilogy
3. Adds Huge Weight To The Death Star Assault

The Death Star plans don't get much of a mention beyond the opening crawl of A New Hope, but ultimately they're the driving force behind the first film. Leia is on the run with them, gives them to R2-D2 as he evacuates the ship, he finds Luke who in turn is found by Obi-Wan, they then take them to the Rebel Alliance (in a roundabout way) and they're used to plan the destruction of the Death Star. They're the key to everything, but take a major backseat in the story to more exciting concepts like rescuing princesses and daring escapes.
By the time the attack on the station rolls around with half an hour left of the film it almost catches you by surprise, and it's easy to forget that this plan was what set everything in motion in the first place. The briefing is skipped over, and our intrepid Rebels take to their ships. It almost feels like an afterthought.
But knowing now, as we do, everything that went into acquiring said plans... bloody hell. All of a sudden the story of Luke, Han and Leia seems almost immaterial to this battle. Given what was at stake, and the cost it all came at, 3 people on a voyage of self-discovery is insignificant compared to the Rebel Alliance's one and only chance to deal a serious blow to the Empire. A New Hope's finale now feels huge.