It was a difficult job for the producers of CSI to fill the shoes of William Peterson, however Laurence Fishburne is a great actor who has done very well with the lead role. Now, comes word that he's decided to move on. In addition, Marg Helgenberger is taking a reduced role on the show this season, leaving the producers with some big shoes to fill on the CBS classic hit crime drama.
Laurence Fishburne is one of Hollywood's greatest actors. An actor of his caliber was really needed to fill in for the the role of Gus Grissom(William Peterson) in the series. Finding a top flight actor who carries around the charisma of Peterson or Fishburne is very difficult. Few actors are legends like these two.
Likely, CSI has a few more good seasons in it before the series is retired. However, both spin-offs, CSI MIAMI and CSI NY are beginning to suffer from softer ratings and both are just about only head's above the cancellation bubble right now. The CRIMINAL MINDS spin-off failed to be renewed for next season, leaving CBS with a few series and franchises that are beginning to soften in ratings from their peak years. But, a revolving door for actors is never good for any series.