There was a moment towards the end of "Dual", where the writers could have laid the foundation to a more exciting future for this ailing show. Regrettably, and no doubt to its ultimate peril, they declined.
As Peter injected himself and flew Nathan from the burning Pinehearst, the point which Nathan has been striving to make towards the end of the last few episodes was vindicated. In the right hands, giving people powers CAN be used to do good and, as Nathan had said earlier, "don't we have an obligation to help the world?" The writers could have embraced this moral dilemma through this one scene, as Nathan yells at Pete "why'd you do it!" Sadly, however, Peter replied with a somewhat bemusing "because you're my brother", and therein any hope that the show might graduate from a teenage target audience evaporated. The writers seem content with their rather superficial vein of melodrama, and display little ambition of rising above it.
Despite what Mohinder may profess during his philosophical nonsensical narratives each week, the line between good and evil is actually pretty definitive in "Heroes". We are force-fed things in black and white, and no thought or consideration will ever be given us as to the fact these boundaries might cross. The majority of the characters in Heroes blindly go about their stories swept along wherever the plot might decide to take them, with little to no depth or thought afforded to their actions.
Nathan however, has tended to buck this trend, his character compassionate and more complex. It was my opinion that Nathan was the "Hero" of the show's first season; a frequently troubled and conflicted character, it was ultimately the good in him that took the decision to save New York. Amidst a third season where a profusion of cardboard characters have inexplicably changed sides from one episode to the next, Nathan has remained as one of its more thoughtful and interesting contributors. It would seem from the preview of volume 4, that he too has now been tossed on the scrap heap to serve as another plot device. Shame.