Because Jo has said she is a christian; we then think about, what is the main act or miracle Jesus is known for? Dying and raising from the dead. Which she said before that came out that if people know her religion it would be easy to figure it out. Now, she may have changed it a bit since then. Yet, the fact remains that the "Death and Rebirth" issue is the most prominent part of Christianity. So therefore, that would be the number one thought. Because it deals with ones death. Evil must be triumphed over, and maybe death and rebirth will conquer that just as it did in the Bible. The question is, is it Harry's death or is it Dumbledore's? That is why I think it is quite possible for Dumbledore to come back. He is a very fatherlike/Godlike figure in the stories. He is basically everything people would want of a benevolant god. Think, he died to save Draco, and Draco can represent all of the people out there in the world. The very same people who thought they hated someone, but didn't realize how much that person loved them.
Ok, enough of that, I feel like I must sound like a preacher.
tg
PS The book will of course end with a sense of emptiness. You know why? Because it is the last known book of the series we will have.