Never had any desire to gamble on the ship. Seems a bit depressing to me (just my opinion). I'll save my gambling for Vegas, though I'll admit gambling has lost most of its fun for me anyway.
In my view, Crystal would be smart to convert that area into a "fun" space. Ping pong, arcade games, etc. Maybe keep around a casino felt or two for people to sit down and play poker. The kids' club is great for the youngest guests, but it's a little babyish as the kids get older.