Pixar has caused upset within the animation community by replacing the director of upcoming movie Brave. The problem isn't that a director was replaced mid-movie, however, but about the replacement of this particular director.
The news that Brenda Chapman will be replaced by Mark Andrews on the project has provoked such upset because Chapman was the first female director not only in Pixar's history, but the first to have solo-directed an animated movie from a major studio. To make matters worse, Chapman - who wrote and developed Brave - has a strong history within the industry, having been involved in the development of The Little Mermaid, Beauty And The Beast, The Lion King and The Prince of Egypt, to name just a few. The charge against Pixar now is one of sexism, a charge that's been leveled against the studio for years, due to their male-centric stories and iconography (spacemen, cowboys, cars). It may not be true, but it's going to take a real effort to convince everyone else of that now.