That's usually the case with a lot of third installments in my opinion. For example, I had no idea where
Spider-Man 3 was headed in terms of villains. Venom came as a complete shock. Same goes for
Terminator 3. After the long wait from the second film I had no idea where they were heading with a third.
Some "threequels" write themselves, though. I think most fans knew exactly where the third
X-Men film was headed after the visage of the Dark Phoenix surfacing at the end of
X2. We all knew what
Revenge of the Sith was going to be about. That was obvious.
Chris Nolan certainly didn't leave any clues at the end of
The Dark Knight, that's for sure. Even more perplexing is David Goyer commenting that
Batman III might not feature traditional, known villains from Batman's Rogues Gallery.