Painting brick is tricky to do well. You had better have an artistic sense. If you do, it is possible to add some dabs of paint here and there to change the overall look.
Another possibility is to cover up the fireplace with something. That is what we did. We have a 1950's ranch with a very dated fireplace that covers the entire wall in our living room. It is truly awful. My wife found a rosewood room divider which she put on the right side. On the left side she put an easel with some pictures on it. The brick fireplace is still quite ugly but it does not stand out like it used to.