Disney controls everything on Castaway Cay and they do a fine job. Of course it helps if the weather cooperates as this is primarily a beach experience. There are plenty of activities but most are outside. The BBQ provided is not bad. There is adequate seating in the covered pavilions for lunch but of course you could return to the ship to eat if you wanted to go there. The beaches (there are several) were not crowded and there is a shady spot to play table games.
Some of our party did the water slides and some just took the tour. Those that did the slides thought they were terrific. Those that did not visited the aquarium and Casino at Atlantis. They had a good time also