The new Harry Potter movie is dark in ton, and I love it. I think that this is the best movie in the series, followed closely by the third movie.
But what makes the dark tone lighten is the love angle between Harry and Ginny, and Ron and Hermione. They are now buffed (esp Ron), and the final installment in the franchise is being wrapped up because the kids are already old.
In fact, Hermione is going to college already. I mean, in real life.