I finally got round to seeing it recently, and here's my stance:
Beorn I feel should have gotten a bigger introduction, and more screen time. What you see of him is nice, but there's very little of it, and considering how he ends up killing bolg I would count him as a pretty major character.
The mirkwood scene I was pretty happy with. I liked how the forest messing with their minds was presented, and the sense of being hopelessly lost.
Thranduil I was also happy with. I liked the interactions with him and Thorin.
Legolas's presence I was slightly miffed with. He was forced into a lot of scenes, though it was excusable in that when he's introduced in LOTR he's introduced as a prince of the mirkwood elves.
Tauriel I couldn't stand. Like Legolas, she is shoehorned into lots of scenes unnecessarily, but with even less explanation than legolas. She was also major in the 'Fili gets injured' sub-plot, which is my biggest problem in the movie (more on that later).
The escape form the elves I was happy with.
The river chase scene I felt was a bit excessive, and also ties into the 'Fili gets injured' sub-plot.
Bard's introduction diverged from the book a lot, but I can understand the change there, as I would understand how his introduction in the book would not work in movie form.
Similarly, the whole thing about a damaged scale I can understand the change.
The departure for erebor I has infuriated by. I don't understand how the third movie will be able to depict the siege of erebor if a third of the dwarves aren't actually in erebor. I suspect there will be a lot of rage-inducing changes in the third movie as a result of this.
The attack on lake-town I felt was completely unnecessary, as it was there to facilitate the 'fili gets injured' sub-plot, which is what I hate most about the movie.
The conversation with smaug I loved, as with the chase scene, though it did get a bit scooby-doo-ish. I was somewhat annoyed by the statue scene, but that was more of a "liquids don't work that way" physics rage than anything else.
I liked the note the movie ended on.
I also liked how Sauron was depicted - indirectly and very powerful.
So in summary - If one were to cut out the 'Fili gets injured' subplot and the unnecesary extra scenes caused by it, I would love the movie. However, that subplot kept being brought up thoughout the movie, which meant I could not enjoy it for very long before the subplot appeared again.