While people complain that Primrose's death in Mockingjay is an insult to Katniss's sacrifice and making it meaningless is stupid. What she did started a rebellion that wouldn't have happened had she not stood up to take her place. Also, if Primrose had survived the war, that would've made Katniss to not have as much of a personal loss than she has. Plus, this sends a good message to idealists: Just because you want something doesn't mean that you'll get it.