Successful storytelling rests on a few basic principles. One of them is this: A story is about someone who changes, who grows through a moral struggle. What is Harry's struggle? Exactly.
Throughout the series, but especially in book seven, even Harry's darkest moments – of self-doubt, of disillusionment, of skepticism about his greatest mentor, Dumbledore – never ring true. Was there any doubt that Harry would fulfill the task set out for him?
The truth of the matter is that Harry the character had nowhere to go. And thus, the overarching moral dilemma of the series, the compelling inner crisis that begged resolution, had nothing to do with our beloved hero.
First principle of storytelling
Back to that first principle of storytelling: A story is about someone who changes. And, puberty aside, Harry doesn't change much. As envisioned by Rowling, he walks the path of good so unwaveringly that his final victory over Voldemort feels, not just inevitable, but hollow.
But there is one character who does face a compelling inner crisis: Snape. With all the debate – and with all of Rowling's clues – about whether he was good or bad, it's fair to say that the sallow-faced potions professor has entranced many readers. His character ached for resolution.
And it is precisely this need for resolution – our desire to know the real Snape and to understand his choices – that makes him the most compelling character in the Potter epic. His decisions, not Harry's, were the linchpin. And his moment with Dumbledore after the death of Harry's parents, not Harry's last duel with Voldemort, is the authentic climax of the series.