Sometimes, it happens that a character is brought back, whether from the dead, or back in a series. When resurrecting a character there is always motive, a purpose, and that motive has to be clear, defined, and essential to the story, otherwise, it might not make sense or have an impact in the story.
Why bring back what was once gone if there is no agenda? It is a risky maneuver for the writer, one that can upset readers more than the demise itself. Of course, for fans of the long gone soul, it is a heavenly gift, like breathing life into the pages once more. For the writer, a necessary duty, a risky endeavor, a solemn event.