I think Katniss had realized Coin was bad before Prim's death, but without that final key death, I don't think she would have killed Coin. She would have killed Snow, gone home, probably lived much the same life she did anyway. But the Hunger Games would have continued, the Capital people would have become the new angry underclass, Coin would have instituted a new dictatorship, and the whole cycle would have begun again. A few hundred years later there would have been another uprising and maybe that was the time people finally just went Doctor Strangelove on the planet and wiped themselves out. So as awful as Prim dying was, I don't think the story could have been resolved the way it was without the death. It just wouldn't have rung true to have Katniss kill Coin.

I honestly never liked Gale. From the beginning I thought he was just a little too angry. Catching Fire really emphasized that and so I felt like it was a natural progression of the character. To have him settle down for life in the country with Katniss and 2.5 children and a white picket fence would have felt like more of a character deviation than what actually happened in the book.

The tragedy of war is a little toned down in Collins' Gregor books since they're for a younger audience, but you get the same themes in them as well. By the end no one is left unaffected by the war. They're different people and not necessarily better ones. Damage was done to them that could never be fixed. That's one of the things that I really love about her books, because all too often in fantasy, we have the little kids run off to war, they hack off peoples' heads for a couple of chapters, and at the end they're fine. No psychological scarring, no need for therapy, no screaming nightmares every night. Sure, the genre isn't meant to be realistic, but I don't think that we're doing kids any favors by portraying war as anything other than awful brutal business. Grown men and women are traumatized by war, if a kid comes away from it totally fine, I'm calling sociopathy.

To relate that to the Narnia books, I've noticed the latter books do delve into that effect of war a little. The Last Battle in particular doesn't shy away from showing the heartbreaking reality of battle. I think Lewis, having been in war, perhaps reconsidered the glossy, sanitized battles of LWW and PC as he continued the series. I don't think any 12 year old kid would read about the battle of Anvard and go "Wow, that sounds cool! I wish I could be there riding around with Shasta!" And I think that's deliberate.