That's the first HP7 ad I've actually liked.

I think the producers of the film are focusing on the couple that the audience of the movies are responding to - Harry and Hermione. There is real on-screen chemistry between Dan Radcliffe and Emma Watson - it's just one of those things that happen - and it affects their characters and the way the audience responds to them.

As for me, because of the on-screen chemistry, I think it should have been Harry and Hermione all along.

As for the books, Rowling can't write chemistry between characters to save her life. So it really doesn't matter so much in that regard.