Nate Dillon’s review published on Letterboxd :
I liked this movie, but I can't understand why they changed the story so much from the book. It wasn't to save time, because they added things that weren't in the book, making the movie longer.
It felt like the changes in the Lord of the Rings movies were made to make the story fit in a shorter amount of screen time. In the Hobbit movies, it feels like they are intentionally trying to make the movies longer and are adding extra action scenes that don't need to be there.
As I said, I like this movie, but they obviously decided that they don't need to follow the story in the book very closely.