Just as Harry had deserved to live, he deserved to have a happy ending. Married to Ginny, with three children, maintaining close friendship with Ron and Hermione and their children...everybody seemed to get their happy ending. Even Dark Marked Draco apparently only karmically paid for his crimes with a receding hairline. The next generation was good to go. It was a happy and satisfying ending. But was it the right ending? Could all of the trauma that Harry had endured during his formative years really allow him to become the content man that we leave at the end of the epilogue? Maybe he should have had a Frodo-esque ending, saving the world but losing himself in the process. It would have been a less satisfying and more unfitting conclusion for children, but it could have worked.
"The scar had not pained Harry for nineteen years. All was well."