2. Sometimes Scenes Should Stay Deleted
I think before the filmmakers go ahead with filming this proposed new footage for the proposed Hobbit trilogy they must ask themselves if the new scenes will benefit the overall story. It seems reasonable to assume that Peter Jackson has already filmed all of the scenes that tell the story of the book and that any additional footage that he films would merely be added world building and character development.
While scenes of this nature do have a part to play in any good film, too much world building can result in the story becoming lost and the pace of the movie suffering. For example, although I enjoy the extended additions for their contribution to the cinematic world Peter Jackson created, I prefer the theatrical cuts because they focus more on the story.
Furthermore, if Peter Jackson did decide to go with three films he would probably include a lot of scenes that ordinarily wouldn’t have made it into the original vision for the two-part adaptation. This could lead to the inclusion of some weaker scenes that may let the movie down as a whole. For example, I am sure I would have enjoyed The Two Towers a lot less in the cinema if they had included the extra Ent scenes that are present in the extended edition because they slow the pace of the movie massively.