Vaughn wanted to shoot that script?
Well, technically, no. He didn't. He got excited, and in a matter of a few days wrote his own draft with Kinberg and Penn with elements that, save for a few of them, never got past the first level of production. Last I knew, Vaughn wanted a movie where Storm and Wolverine fall in love (and have sex, which some people blame on Tom Rothman's desire), a ton of main characters died (and a ton were introduced cameo style), and in general, things weren't any better than what we ended up with. The Cyclops/Xavier deaths were there, and Storm was rumored to perish as well as Rogue in Vaughn's take. In short, all the things that happened in X3 still happened. And FOX essentially told him "That's not going to happen, we have an X3 script already (written by Simon Kinberg and Zak Penn before a director was ever settled on), we'll take some of your ideas, but not the key ones we differ on. THIS is the movie we're going to make". That's my understanding of the situation, and to my knowledge, nearly every article/review/insider report about the film reflects that.
I always assumed he bailed because he didn't like the film the studio wanted to make, but Ratner had no problem with it and just filmed the thing.
Given the timing, Matthew Vaughn appears to have bailed because he didn't think the movie could be shot appropriately in the timeframe FOX wanted. Those were the rumors right before he left the project, and then he left the project. Family reasons were cited, but that appears to have been something of a cover. Maybe there were some creative differences, and that's why he actually left, but as I recall, he wasn't bailing until FOX decided it wanted to compete with SUPERMAN RETURNS. At the time, he'd cast several of the key newcomers. So I don't think it was entirely a creative difference.
Yes, he's a hired gun if that's the case. You don't have a problem with that kind of director?
Hired gun in what sense? That the man is paid to direct films? Or that he's paid to direct films other people walk off of?
No, I don't have a problem with Brett being paid to direct a movie, because he's a professional director. And no, I don't have a problem with Brett Ratner coming into X3, knowing the script was what FOX wanted and directing it to the best of his ability. Why would I? That's how directors and studios tend to work, and this was clearly a "special" case. That said, Ratner did make a few key changes, with FOX's apparent blessing, cutting a Washington DC sequence (may be budgetary) and moving the bridge sequence from the middle of the movie to the end of the film. He also added a few characters to the Brotherhood.
What am I supposed to have a problem with, exactly? That he didn't stand up to FOX as much as he could have? As much as I'd like to pretend that every director making a major superhero movie gets to have all the say...and gets to have a hand in the creative process...that's just not how it tends to work with FOX's bigger budget superhero movies.
With X3, I have a problem with the studio, and Vaughn (who, as a professional, took on a project he apparently wasn't sure he could finish, and then badmouthed the man who came in to clean up his mess afterward). Not Ratner. Ratner did a heck of a job, considering what he had to work with, which wasn't all bad, but was a mixed bag, at best.