I hate it when they take a great movie with a complete storyline and try to pin on two more films to make it into a trilogy. It's not a trilogy; it's two separate stories told in three movies. If there was any possibility of the first movie being so popular that it would inspire a sequel, why didn't you leave any openings whatsoever for the story to be continued? The only good trilogies are those that were trilogies to begin with.
Just look at what a flop Pirates of the Caribbean turned out to be. I'm getting the same vibe from TFU2 that I got from Dead Man's Chest. Both are basically an extended trailer for the third installment.
The Star Wars prequel trilogy, even though it was meant to be a trilogy, is also guilty of this. Episode 1 was a complete story with a beginning and end. Episode 2 basically started all over again and did nothing more than set the stage for Epsode 3. That's two separate stories crammed into one trilogy, not one continuous story like it should be, and it's exactly what they're doing to TFU.
Even if it's not one continuous story, why not three stories? That can work too. The Lord of the Rings was one story but it was also three separate stories. At the end of the Two Towers you had at least been treated to a complete storyline about Saruman that essentially began and ended in the same movie. If Christopher Lee's character had been defeated in Episode 2 of Star Wars, the ending wouldn't have felt so abrupt. In fact, it would have felt like the proper conclusion to a movie mostly about his actions.
The Two Towers was a story within a story. TFU 2, as much as you'd like to call the duel with Vader a climax, was still only half of a story.