I have a couple of issues with this question. First, these are such different things. Reason is not the same thing as faith and imagination. Those two have much in common, but they are not connected to reason. Second, there is no way we could possibly do away with these things even if we tried.
As for the "should" of it, I do not think we should try to or want to get rid of these things. All of them have caused trouble for human beings, it is true. However, they seem to be very important to us. Many people need faith to help them make sense of their lives. We need imagination to help enrich our lives and to help us progress economically (people need to imagine new inventions). We need reason to help us analyze our problems and help to fix them.
All of these different things are important to human life and there is no reason to try to do away with them.