At the end of the 6th book there was a battle between the death eaters and the order members who protected Hogwarts when Dumbledore left. They cut it out so the battle of Hogwarts in the final movie would´n be too much deja vu.
It really bothered me, that Harry was just standing there when Dumbledore was killed. He should hae been stunned like i the book. And also, how is he supposed to know what the horcruxes are, when Dumbledore never told him.
Tom Felton was GREAT in this one though. And Alan Rickman was brilliantly cruel as usual.