He didn't leave a cliffhanger.
Changes did exactly what you want. It had a complete, fully contained story. All of the conflict in the book is resolved before the end of the book. Dresden has solved all of the problems before the last chapter.
Butcher didn't write a cliffhanger to try and con people who have read his last 12 books in to reading 13. He didn't cut the story off before the climax to torture you for a year. You freaking
know that Dresden isn't going to be dead and gone so why does it bother you? All he did was write an intrigue that hints at the next book.
The end of Changes has created zero anxiety in me and it certainly isn't tricking me in to buying the next book. All it does is make me think about the implications; I have considered who could have done it, what the next book will be about and how the resolution of the next book with effect Dresden's ties to various people. If you think that is a bad thing then I don't understand why you enjoy books to begin with.
-----signature-----
If I have burnt my bridges I will walk on water.
If you're on the shore, then you're sure not me, oh
My seething wrath and urge for blood is fueled by searing hate.
I'm X X X bitch, triple X rated.