Laurel has been on a downward spiral since season 2. It's really too bad because she had all the makings of a great character in the first season (aka when the show was actually good). I don't think her death will change/impact anything on the show... so in that sense, it seems to be a rather wasteful plot point. But it fits with the trend of a show committed to lacking direction and using flashbacks to fill the lack of creativity.