I dug up some quotes regarding First Class from Vaughn and others:
“I was amazed at the negativity, though, towards the X-Men world. Not really, actually, after watching Wolverine. But it was quite scary, I was thinking, "Am I going to manage to turn fanboys around and enjoy it?" I thought, the best way of doing it was trying to make a good movie, which is respectful to the other X-Men movies, but not reverential to them.”
“So, what was more satisfying about this one, was because of Stardust and Kick-Ass, I was far more comfortable about bigger budget, special effects, all that ****. But I loved the idea that I could recast every character, set up a new world, and do my version of an X-Men movie. Because, with X3, ultimately, you're following a trend.”
"I don't give a **** about the other ones. For me, I wanted to do my version, and the version where it's more similar to the comics at the beginning. I really enjoyed X1 and X2. I thought Bryan did a really good job. But I think X3, and then Wolverine, it sort of went off, and the whole superhero genre has been ****ed up by Hollywood trying to- just, big explosions and glossy, corny costumes and outfits."
When Fox offered Vaughn the "chance to reboot X-Men and put your stamp all over it", he first thought the studio was joking, but accepted after discovering that it was to be set in the 1960s. The director stated that First Class would become the opportunity to combine many of his dream projects: "I got my cake and ate it, managed to do an X-Men movie, and a Bond thing, and a Frankenheimer political thriller at the same time".
Vaughn said his intention was "to make as good a film that could stand on its own two feet regardless of all the other films" and also that could "reboot and start a whole new X-Men franchise".
Goldman added the film was kind of an "alternate history" for the X-Men, saying that while rebooting, the writers did not want to go fully "against the canon of the X-Men trilogy", comparing to the various approaches the comic had in over fifty years of publication.