If it’s a trilogy, he probably will draw from more source material than the Hobbit. I can see him drawing from Tolkien’s other books of events that were happening at the same time as filler material.
The Appendices are full of material. A third movie could easily have Aragorn and Arwen share a romance and still have time for he and Gandalf to share an adventure in the years after The Hobbit but before LOTR.
The book is less than three hundred pages.
I am a true LOR fan and think he did a tremendous job with the trilogy, yet even in the extended versions he left out some major players particularly in the early stages of the films. Including Tom Bombadil who aided the adventurers in the Old Forrest prior to their stay at the Inn at Brie. He was a relatively important character and was mentioned at the Council of Elrond as a possible keeper of the Ring of Power. He was also in the ending chapters. The Rape of the Shire and the reclamation of Frodo's Home from the Sackville baggins's was left out of the LOR trilogy and it's extended version even with almost thirteen hours of film.
I only hope that he doesn't do to the Hobbit what he did to King Kong. The Movie was very good in some parts but was in desperate need of an editor. He could have lopped off a good 30 minutes or more of the film and made the picture much better by having LESS film.
Hopefully he will be far more faithful to the source material than he was for Lord of the Rings.
I’m not referring to omissions. I’m referring to deliberate alterations in the movies.