My favourite part was how they leave all the cool parts for later films so they make more money
Okay, but seriously, I like how they added some ties to the Ring trilogy that weren't originally in the book! Like the necromancer in the ruins (Sauron of course), and meeting Galadriel and Saruman in Rivendell. It makes the story fit better into the timeline of middle earth, because since Hobbit was his first work in the universe, Tolkien couldn't really add anything hinting to future or past events that he hadn't made yet!
I'm especially glad that what was added was taken from other works set place in Middle Earth, and not completely fabricated for the film. The pale orc for example, while he most certainly isn't in the original book, did actually fight against Thorin in that battle in the official timeline. Only exception being that in the "true" canon, Thorin chopped his head off instead of his arm right there and none of this happened hahaha.
Guess they still needed to add an antagonist so the film wouldn't feel boring.