Indeed. And that's where they've gone wrong, IMO - they're caught between two stools.
As an adaptation of "The Hobbit", these films fail by being too long, by being too full of padding, by including too many needless cameos of the previous cast, by adding too much material, and by significantly changing the tone. Plus, splitting a single novel into two films (never mind three) should be outlawed as an offense to good taste - it never works well.
As a prequel to "The Lord of the Rings", these films fail because of that pointless subplot with the dwarves and that dragon.

Or, mostly, because Peter Jackson and his team are having to invent too much stuff to flesh out the narrative, and they're just not Tolkien. Plus, prequels suck.
RangerWickett is right - the best thing for these films would be for someone to strip out everything that isn't in "The Hobbit", re-edit what remains, and turn it into a single 3-hour film.