Firstly, I write with the assumption that you, dear reader, sustained a degree of disappointment with An Unexpected Journey. A solid preamble to be sure (if rather protracted, to the discomfort of the less bladder controlled), but something of a narrative mess. Furthermore, the high frame rate (HFR), coupled with the busy nature of 3D, left much (or a lot less!) to be desired. Middle Earth felt familiar, but less genuine.
The aforementioned issues compounded the usual problems encountered by the first in a pre-concieved trilogy (so the Matrix, Raiders of the Lost Ark, and initial Pirates of the Carribean are exempt from the rule). The first film has to introduce the core characters, build audience sympathy, thoroughly illuminate the many strands of the plot, and remain (in this case) reasonably close to the book. The curse of the first film is that the pay off for all this trouble does not occur until its sequel.
Think of the movie sagas that were conceived as more than one film in the first instance. The Empire Strikes Back is often considered the jewel of Star Wars. The Godfather Part II is the finest film Frances Ford Coppola has ever made. Every issue plaguing the success of the first movement in these grand cinematic endeavors is absent in the second - by definition.
Aiding The Desolation of Smaug is the slight modification of the effects, and the year we have had as audiences to come to terms with HDR. If you are one of the unfortunate viewers for whom HDR and/or 3D is always trouble, then you don't have to try it this time. Simply see the film in old school glory and enjoy yourselves.
Greame Tucket mentions in his Dominion Post review that the difficulty with the Hobbit from a screenwriting perspective is the great proportion of characters. The company of Thorin Oakenshield sits at fourteen and though all their names may be hard to keep in mind (I still confuse Oin, Bifur, Dwalin, Orry, and Norry), their individual characteristics are so particular, and thanks to Journey so familiar that you shouldn't get lost. The classic barrel sequence, and Bilbo's introduction to Smaug are highlights - Oscar fever is rightly warming.
I promised to be terse and so I shall, the reason to go to The Desolation of Smaug is it vindicates An Unexpected Journey, and proudly hits the mark of a great film.
