The Harry Potter films I have seen (I and III) have relied on generally unmotivated plot twists with surprisingly little foreshadowing. Interesting for film adaptation because in general, this kind of thing rarely happens in film itself. Talking the other night about In The Cut there was a fair bit of discussion about the obviousness of the twist in it. It was mostly motivated by knowledge of the ways films work, and that the noughties way is to avoid extraneous characters and every action has a meaning. Cinematic slight of hand demands that the number one suspect is rarely the killer, and indeed that the killer usually someone you have not suspected. In The Cut arses this up by having only four male characters, three of whom are suspects. It is obvious who did it.
The cult of Potter demands that the books are reproduced relatively faithfully. This in particular means little culling of supporting characters. Usually the suspected villain will be foreshadowed: Snape in the Philosopher’s Stone, Sirius Black in Azkaban – usually to be replaced by a character we either don’t know or was completely out of the picture. This actually is rather refreshing, though oddly as a film it is generally preaching to the knowledgable. What is undeniable though is that clever casting does most of the work for them. Oldman and Rickman are well known for their villainous roles, and hence much of the work is done. The films may be an overstuffed, breakneck ride of insignificance – but at least they offer the viewer a way out of traditional plotting.