Change of director - why?

Today my group and I decided that we needed to change the director of our film. Our originally director was James Wan but we thought as he has directed and producer scary films like insidious and paranormal activity he didn't fit the genre that our film was in. We looked at other directors like Pierre Morel because he directed Taken and that was a thriller. However he isn't a very known director so we thought he wasn't a good choice so we looked at the director of Prisoner which was Denis Villeneuve. I then looked at the past films that he has done and none of them relate to the genre we are looking into, so we decided to look into David Fincher and he has recently directed Gone Girl which is a crime/thriller and this is the genre our film is in. So my group and I decided to pick him as our director. 

James Wan was our old director of our film. 

David Fincher is the new director we have picked for our film.