The movies are supposed to add to your enjoyment of the books! I actually like the way JK Rowling writes, and the way she storytells. It's not always about action scene after action scene. The description and narration is worth it! And the best part about these books is that they actually get kids to read 600 to 700 page books! If you think about it, it is pretty amazing that kids actually sit there and re-read these books time and time again. I think it's great! Kids are way too enamored with TV, the Internet, computer games, and video games.
Correction: It is the Department of Mysteries, not the Chamber of Mysteries. Also, it would take them WAY too long to show how they got into the Ministry. In the book, it says that they get through the Telephone Booth and once you're in there, you get questioned by this "secretarial voice" (ie. what is your purpose inside the Ministry, who are you, etc.), they get these badges that they have to wear (ID tags), then the booth descends into the Ministry's Atrium. From the Atrium, they have to make their way to the elevators, and take the elevators all the way down to the Department of Mysteries.