The school takes these kids in at the age of 10. I'm not sure you could call anyone good or evil at that point. By the time they finish they are only 18ish and again, you cannot really make a call on whether or not someone is going to grow up to be a good or bad person much less evil. It is fairly easy to make these judgement calls about characters in a fictional world when you are privy to exactly what they are thinking.

As far as Fenix's questioning why they don't just use Veritaserum on people to get the truth out of them instead of having to torture the truth out of them-- My best guess is that you could find ways around it. I would imagine the most straightforward way would be to alter or block off parts of your memory so that you wouldn't be lying if you said something, or that the consequences of using the potion are too severe.

As for Fudge's refusal to believe Dumbledore's assertion that Voldemort had returned in The Order of the Phoenix, you would need to read the book to get a better handle on the fact that Fudge was not simply being a moron. He was concerned that Dumbledore was aiming for his position since it was always widely believed that Dumbledore was the best person for the job. There were more politics to the issue, but basically that is what it boiled down to.

Back on topic: The movie was pretty good, I liked it better than the last couple as well; despite the fact that it did have a bad habit of skipping around from point to point without explaining things very well. I think they are struggling to cram everything in to the movies at this point which is why the first two were far more satisfying (they were far shorter than the later books). As far as Harry just sitting and watching Dumbledore goes, they didn't have much of a choice other than to portray it that way. If they went the book route then Harry would have been frozen by impedimenta and covered with his invisibility cloak, and then you are left with Harry's reaction being cold and lifeless because he is frozen. As far as Harry not running in: Harry may be brave but he isn't stupid, there would have been no way for him to even attempt to take on that many wizards.

The last 2 movies have the potential to make up for the shortcomings of the last few and still have some epic left over to be the best movies in years so long as they don't screw it up.