That's cool, you may think. After all, did he not return to shoot some finishing details and touches to each of his Lord of the Rings movies before they actually went to theatres?
Well yes, but his reasoning for going back is nowhere near as innocent or "small minded".
He wants to continue filming in the hopes that ... the studio will let him...
Expand the second movie of the two The Hobbit movies... into a third!
Suddenly, The Hobbit duology went may turn into a trilogy.
To that I say WHAT?
At around 300 pages long, that averages 100 pages of the book for the movie. And if any of you have read 100 pages of those books, it doesn't (or rather shouldn't) take very long to go through 100 pages. You can tend to get through them fast, very fast.
Now granted, the Battle of Five Armies lasted maybe... 5 of those pages, if even, and that's mostly because (spoilers) Bilbo got knocked out at the beginning of it while wearing his then-benign-but-later-very-evil ring (note with a lowercase here) by an errant Goblin swing (end spoilers).
That's not going to happen in this movie. Not with Peter "bloody-long-my-bloody-battles" Jackson at the helm. When he can extend the Battle of Helms Deep to a good 1/3 of the Two Towers movie out of a single chapter of said book, you can bet that the Five Armies is going to be a prolonged epic bloodbath where it will actually feel like five armies are involved and not just a bloody hobbit versus the world incident.
Seriously, expect blood.
Also, as it stands, apparently they're also going to be filming stuff from the Lord of the Rings appendices that didn't or couldn't be worked into the first triology helmed by Jackson. So there is that too.
Which is all well and good, and yet, all I can think is...
Don't do it Peter Jackson!