As per the aforementioned opening quote, Bacon is frank about Vaughn's method's, but he also has a ton of respect for the filmmaker.
The actor said Vaughn was candid and not crass. "He doesn’t do a lot of takes," he told the LAT. "He does zero in on things. I remember once he yelled, ‘Stop twirling your mustache!’ And it was totally on point. I was starting to get into some kind of idea of villainy and not staying true to who Sebastian was. As an actor, I can appreciate that.”

We've already heard of some of Matthew Vaughn's sequels ideas, some of which may involve JFK's assassination, some of which could see the films entering the '70s or '80s. Right now it sounds like the film would need to be a major hit for him to return.
"Yeah, if the film's a hit, I'd be very interested in doing a sequel," he told SuperheroHype. "I really, really enjoyed… the team I had on it were great, and the hard thing is creating a new franchise, so if it works, it would be fun. My ideas are much bigger for the next one. I've got some really big … I'm surprised everyone is calling this a really big epic movie, and I'm thinking, 'Wait until you view the next one if you think this is epic, the next one you won't believe what happens.'"

While Bryan Singer and 20th Century Foxed Picked All The 'X-Men' Characters In The Film Before Matthew Vaughn came on board, there was supposed to be one more mutant character.
"In the draft they gave me all the characters were in there. We cut Sunspot, because we didn’t have the time or money," Vaughn said. "They couldn’t make him work, it was a pain in the arse."

Michael Fassbender didn't bother watching the 'X-Men' performance of Sir Ian McKellen or any of his other work.
Initially his idea was to reverse engineer the performance and work backwards, but after speaking with his director, they decided to go another way. “When I first found I’d got the job, I thought about studying Ian McKellen and getting my hands on anything I could when he was a young man on screen and studding his physicality and voice," Fassbender said. Then I sat down with Matthew [Vaughn] and we decided that wasn’t the way he wanted me to go and so I ditched that idea totally and used the comic book source material.”