This is no longer really the story of The Hobbit anymore, as we used to know the book. It's basically become an adventure made up by Peter Jackson & Co. loosely based on The Hobbit. So many details have been changed and so many new scenes have been added, that it has almost become plain ridiculous.
The reason for all of this is most of all, that there were never enough material for 3 far too long movies in that short book. Hell, there is barely enough material for 2 movies, even if they still wanted to merge them as much with The Lord of the Rings [2001-2003] as they clearly try to do.
But the more Hobbit movies you can make, the more money you can make. I won't believe any other explanation than this was all about the money, and so they had to stretch many scenes in all eternity and plug in tons of irrelevant crap, self-invented side-stories and then of course add tons of pointless action scenes, all of which get awfully boring to watch after a short while.
Even if Smaug the dragon looks pretty awesome indeed, why does every scene have to be filled with so much lame action? In the end it feels more like fucking Godzilla  - pointless action and no content. I guess that's what often happens with 3D movies. They forget about everything but the action scenes. They even forget how to make great action scenes. This just becomes even clearer when you watch it in 2D, like I did.
I liked the first episode An Unexpected Journey  better than part 2 - even if part 1 wasn't perfect either - but I'm not particularly looking forward to the last episode of this. I feel pretty sure already, that I won't be liking it a lot. But I guess I can't help myself by then and I'll probably go see it anyway. If nothing else, that makes it easier to complain about it. :)
One thing is however certain, I'll never re-watch these Hobbit movies again on bluray. Jackson & Co. have lost much of that magic that is found everywhere in the LOTR movies. Also I won't be giving a fuck if they should ever make extended versions. I've seen more than enough of this already, and more is not always better.