Admittedly, we know very little about what caused Edgar Wright to step down as director of Ant-Man on Friday, other than the parting was "amicable" according to Marvel. But that might not have been the case at all.
According to Latino Review, Wright and Marvel had irreconcilable differences over the script:
About 3 months ago, Marvel had notes. The meat of the notes were about the core morality of the piece, must include franchise characters. etc., These notes came from the big four at Marvel. Joe Cornish and Edgar Wright did two drafts to try and answer the notes without compromising their vision.
6 weeks ago Marvel took the script off them and gave the writing assignment to two very low credit writers. One of the writers were from Marvel's in house writing team. Edgar stayed cool, agreed to stay on the project, and read the draft.
The script came in this week and was completely undone. Poorer, homogenized, and not Edgar's vision. Edgar met with Marvel on Friday to formally exit and the announcement went out directly after.
Edgar & Joe were upset by the sudden, out of nowhere lack of faith in them as filmmakers. Fiege had always batted for them but this felt like it came from the higher ups.
Directors and studios fight over scripts all the time, especially with summer blockbusters. What's weird here is that Marvel's scripts have generally been pretty good, right? I can imagine Wright wanting a stranger, goofier film than Marvel had wanted, but how did it get to this late date without Marvel and Wright figuring this out?
Meanwhile, Marvel directors James Gunn and Joss Whedon have made statements on Wright's departure, which aren't exactly comforting. Here's Gunn's, from his Facebook:
"Sometimes you have friends in a relationship. You love each of them dearly as individuals and think they're amazing people. When they talk to you about their troubles, you do everything you can to support them, to keep them together, because if you love them both so much doesn't it make sense they should love each other? But little by little you realize, at heart, they aren't meant to be together – not because there's anything wrong with either of them, but they just don't have personalities that mesh in a comfortable way. They don't make each other happy. Although it's sad to see them split, when they do, you're surprisingly relieved, and excited to see where their lives take them next.
It's easy to try to make one party "right" and another party "wrong" when a breakup happens, but it often isn't that simple. Or perhaps it's even more simple than that – not everyone belongs in a relationship together. It doesn't mean they're not wonderful people.
And that's true of both Edgar Wright and Marvel. One of them isn't a person, but I think you get what I mean."
A very diplomatic answer, but it's also what Gunn would say if he thought Wright was completely in the right but he wanted to stay on Marvel's good side in order to direct Guardians of the Galaxy 2.
Meanwhile, Joss Whedon's "response" is even more potentially troublesome:
Is this a show of support for Wright? Does Whedon thinks Marvel was wrong here, and doesn't mind saying so because he knows he's Marvel's golden boy? Is it simply a salute to a fellow director? IS EVERYONE SUPER-PISSED AT MARVEL OR IS EVERYTHING ACTUALLY COOL? And most of all, is Marvel going to give us a shitty Ant-Man movie?