I agree with pretty much everything here! I enjoyed the movie, was a bit let down by some things and some of the choices made but I think it will generally work pretty well in context when the third film comes out. Kind of like The Two Towers actually.
The unlikely romance was really dumb. It didn't even vaguely serve the plot... its sole purpose was as the excuse to get Legolas to come to town and f up all those orcs. Most of which I have to admit was pretty cool, but it was highly unnecessary, and took time away from other characters you actually care about.
I do actually really enjoy all of the other extra stuff put in - the stuff drawn from Tolkien's actual writings especially. As much as I like the book and admire its pacing and economy in storytelling, I don't think a straight adaptation would have been as satisfying. I suppose I did enjoy the straightforward animated adaption but I last enjoyed that when I was a kid and I'm not sure I would as much now.
One thing I'd like to mention not covered in this review is the high frame rate. I went to the double feature last night (the first film at 8:30, second at midnight) which was presented in the high frame rate. I saw the first one last year in IMAX, and I just didn't realize how much I'd missed until I saw the HFR version. The elaborate escape sequences in particular are astonishing to behold.
It does look a bit wonky at times but over all I think it adds a lot to the experience. Especially with the 3D, which is astoundingly good at the higher frame rate. Easily the best I've seen.
I think there are more than enough scenes featuring events and actions that change Bilbo, but they're definitely not given enough time. It barely feels like he's in this movie. The most effective scene showing his character development in the first film was when he decides not to kill Gollum (following Gandalf's advice), and then the follow up when he tries to save Thorin. It's sort of presented in the second film that he undergoes similar changes (as mentioned in the review), but it definitely doesn't really feel like it (other than a "precious" anger-state).