A camera produces motion blur when it's not fast enough to resolve the image in a single frame. It will do little to enhance the illusion of reality. It's a cinematic effect. In a game, the experience is not passive, it's active, and when you are actively involved in a reality you don't sense or perceive motion blur. As far as check boxes go, I think the motion blur off check box will get a lot of hits.
Depth of field is even worse.
Again, this is a camera artifact. When we are watching a movie, typically one part of the scene will be in focus while other parts will be out of focus. Now this works fine in movies, which are passive experiences. In life, and in games that try to create a sense of reality, or a believable reality, there is no depth of field. You direct your attention where you want.