Always blunt, Vaughn didn't worry about pleasing the fanboys.
"I didn't give a shit, to be honest," the director said matter-of-factly."I got pitched a story by Fox as being set in the Cold War with the backdrop of the Cuban Missile Crisis. [They said] I could go off and make my 'Bond meets X-Men' movie, and that's really all I cared about."

While the screenwriting credits ultimately went to four people in total -- Ashley Miller, Zack Stentz, Jane Goldman and Vaughn (and six people vied for credits) -- Vaughn suggest he and his writing partner Goldman are responsible for the script you see on the screen.
These writers have all crossed paths before as well on another superhero film that Vaughn almost directed. "[Miller & Stentz] rewrote the '[Thor'] draft that I did with Mark Protosevich, but I thought that draft was better and they shouldn't have rewritten it, and we rewrote their draft [of 'X-Men'] and made it a lot better," Vaughn said. "[We] swapped projects and one was for the best and one wasn't, so yeah, we did a major page one rewrite and Jane and I had to do it bloody quickly."

Vaughn was even more forthcoming in an interview that Obsessed with Film was part of. There were other writers who’d established part of the script, right? "Not really, not that the WGA think that, the fuckwits," he said. "No, but Jane Goldman and I wrote the screenplay, threw everything out and started again. Sheldon Turner managed to get a ‘story by’ credit , he wrote a Magneto script that none of us even read. I didn’t even know that, I mean I was like who the fuck is this guy? Hollywood’s got its own way with dealing with these things."

With 5 cinematographers on the film, only one of them got credit -- John Matheson. Why?
"Welcome to Hollywood," Vaughn said. "How come all these people who did fuck all on the screenplay get these credits? I think John did the most though so that’s why – John Matheson did a great job by the way – 55%? I should know. He came on half way through the shoot. Again it was good for me. Normally I’m far more collaborative with DPs, here I became a bit more of a megalomaniac – as in look someone has to take control, this scene’s about the camera being there now. Normally I’d ask the DP, what do you think etc, so it was good to get out of that zone."

"X-Men: First Class" is already almost 2 hours and 20 minutes long, but according to co-screenwriter Jane Goldman there's a lot more that was cut. Maybe the 3-hour version on DVD?
"There’s such a lot that was shot which isn’t in the film, most of which is the absolutely right decisions," Goldman told Bleeding Cool, noting that a lot of what was cut from the extra character elements that would have likely lent some of the heroes more depth, but would have made the film simply too long and unwieldy.

"The most important thing, and I think the intention always was that the relationship between Charles and Erik to be central," she said. "I think that as the film evolved it became clear how powerful that was. It was important to not trivialize the differences in their ethics and outlooks by not having it to appear to be about one person. Sometimes things go just because of length, but it was also sometimes in service of actually allowing the Charles and Erik relationship."

One of the characters who got short thrift was Rose Byrne's Moira MacTaggert CIA agent and in doing so, the film shifted in its depiction of sexism.
"Moira is a really strong character and her involvement is massively important, but in earlier iterations, before we came along, there was a sort of love triangle thing," Goldman admitted. "We had already very much drawn back from that but it was ultimately a matter of drawing back from that even further.When you write a screenplay, it’s the combination of things you put in that convey what you want the character to be. When it reaches the editing stage it is no longer in your hands so it’s obviously not going to be exactly the way you planned it. In service of the film, these cuts were the correct decision, but in the service of Moira’s character, it doesn’t give a full picture."

"I think there’s definitely an element of '60s sexism, which is supposed to be not-a-good-thing, running through the movie, though unfortunately sometimes, when a film is edited you end up with a thread seeming that you’re not following all elements of all threads. There was much more of story about Moira being oppressed."