Religion: What is the purpose of a New Heaven?

In Revelations, it says that God will make a new heaven and a new earth. I get why making a new earth would be advantageous, but why a new heaven. I though heaven was paradise, as in, without imperfections. Therefore, why make a new one if there are no imperfections which means there is no way to improve it. The only thing I can think of is that Heaven is imperfect.