Simon Kinberg comments on Fantastic Four

"The biggest thing I did on that movie, I think, was transforming the villain of the film. That was an ongoing and continuous process over the span of production because we just needed to make sure that we got the villain right because he is probably the most famous villain in the Marvel universe -- Dr. Doom." 

"It actually was the basis for so many different villains and so many different comic books and even Darth Vader. He's the sort of uber-villain that they needed to make sure they really nailed and Julian McMahon plays him in the movie and did a fantastic job with him. But I was also working on the other characters and the other scenes and the action sequences that always transform as you're suddenly in the space and there aren't walls that are supposed to be walls and stuff like that. That was also a very fun process. I went up to Vancouver a few times to work closely with Tim and the cast. As somebody who was just a huge fan of the comics, it was just a thrill to suddenly see The Thing played by Michael Chiklis actually embodied and walking around was a pretty surreal stunning incredibly exciting thing -- no pun intended."

Source: The Hollywood Reporter