According to Hypable on Dec. 14, a press event involving Peter Jackson and "The Hobbit: The Desolation of Smaug" film gave credence to the cliffhanger-like ending of the film. Jackson explains why he ended it the way he did at that point and thinks that the audience has no real reason to complain.
"I remember when I was – I must’ve been 17 or 18 years old – I remember The Empire Strikes Back had a big cliffhanger ending and it was like three years before the next one came out.” By comparison, “We’re being pretty generous. And actually, as a Breaking Bad fan I was hanging out a long time for that last half season this year. That was a big gap too".
The director also had emphasized that it's not often that films are done in segments like with "The Hobbit" series of films and in fact there had been a lot of discussion on where to make such stopping points at the end of said movies. At this point "The Hobbit: The Desolation of Smaug" is said to have been the most climatic ending of its kind in any of the Middle-Earth series.
"The Hobbit: The Desolation of Smaug" is currently in theaters.