The Hollywood Reporter has a quick Q & A with Hellboy creator Mike Mignola concerning his design work on Guillermo Del Toro's film adaptation of The Hobbit. The comics legend was brought in for a week to lend a hand on pre-production designs, but felt that he really wasn't needed -- not when he's sitting beside the same artists who successfully established Middle Earth for Lord of the Rings director Peter Jackson.
I guess that answers some questions about Del Toro's design approach. While it sounds like he's looking for ways to make it his own, he's also keeping it in visual line with Jackson's established universe. Mignola has a very specific design sense, and even he seems to think that his work won't be as visible here as it was in previous projects like Atlantis: The Lost Empire or the Hellboy movies.
I've been a Mignola fan since Rocket Raccoon back in the 80's, and I'm always pleased to hear him involved on any project, whether on film or on the printed page.