Critics say that saving the cheerleader in Heroes season 1 didn't actually matter when it came to saving the world - here's why it did. Although Heroes is notorious for a rapid deterioration in quality in later seasons, the show's debut run was refreshing, pioneering superhero television that focused on human aspects in a way that hadn't yet been done on the small screen. Heroes became a ratings smash for NBC, and at the core of the first season was a catchphrase that rallied both characters and viewers: "save the cheerleader, save the world." This single line would go on to become arguably Heroes' most memorable aspect.
The iconic quote comes from the climax of season 1's fourth episode, "Collision," when a version of Hiro Nakamura from the future travels back in time to meet Peter Petrelli. Hiro claims to come from a timeline ravaged by a devastating explosion, and has been attempting to unravel history in order to find out how the tragedy can be prevented. The time-traveler tells Peter that "the cheerleader" is the crucial factor, and if Peter can save her, he can save the world. Under the mistaken belief that the explosion in New York is triggered by the villainous Sylar, Hiro claims that he can kill this menace and prevent the incident, but not if Sylar gets to Claire first and steals her powers of regeneration.
Despite the popularity of the phrase, many fans claim that saving Claire actually had very little bearing on saving the world. Peter keeps the cheerleader close at all times, still believing she'll be vital in the final act, but ultimately realizes that it's he, not Sylar, who will detonate. Since Claire is the only person who can get close enough to shoot Peter, this appears to be how she saves the world. Alas, as Claire struggles with the thought of shooting her uncle, Peter's brother Nathan appears to fly his brother to safety, protecting New York from the explosion and simultaneously proving that Claire didn't really need to be there.
It could be argued, however, that Claire had already saved the world long before Peter started going nuclear, and that she wouldn't have been able to do so had Peter not rescued her from Sylar in "Homecoming."
When Nathan arrives in the nick of time to whisk Peter to a safe distance, he quotes a line Claire said to him earlier, "the future isn't set in stone." This echoing of Claire's words confirms that it was she who convinced Nathan to go against his mother's grand plan and stop Peter from exploding. Had Claire not been present, Nathan probably would've escaped the city as per Angela's scheme.
Working the plot back even further, the only reason Claire gives Nathan a piece of her mind is because of her friendship with Peter Petrelli. If Sylar had killed Claire and stolen her regeneration powers, she might not have been alive to change Nathan's mind. Even supposing Claire could've regenerated after being attacked by Sylar, it's still Peter's rescue that saves the world. Hiro tells Peter to save the cheerleader, introducing him to Claire and establishing a sense of destiny. Peter tells Claire about the explosion and trying to stop it, making her buy into his hopefulness. Inspired by her uncle, Claire later chastises Nathan for giving up and not having his younger brother's courage, forcing the politician to reconsider fleeing New York with his mother, and to save the world instead.
This causal link is not overtly highlighted in Heroes season 1 and it may not even have been intentional, so the opinion that saving Claire didn't matter is certainly an understandable one. Other theories suggest that Future Hiro was simply mistaken in his calculations, or that the instruction was actually "save the cheerleader, THEN save the world" but these feel somewhat cheap considering how much emphasis was placed on the line throughout the first season. While it may be convoluted, at least there is actually a chain of events that link Peter saving Claire with stopping the devastating nuclear explosion.