This movie left out the most needed material. I'm really wondering how they're going to do the transition to Deathly Hallows at this point, but we'll have to see in November. The battle at Hogwarts scene was pretty important to Half Blood Prince (and probably the best part in the book) its crazy that they took it out. I had heard, back when the movie came out, that they intentionally left the battle out because of the similarities to the battle in Deathly Hallows.

Also, adding the scene in the Burrow around the middle destroys the beginning of Deathly Hallows too. Don't know how they'll have the wedding at the Burrow, since it burned down in the last movie.