I've been playing island paradise in TS3 and every time i try to explore the cave the sim is reset and sent to the shore. My sim was swimming next to their houseboat and i queued for the to go home. A water taxi came and took them to shore. I found IP in TS3 to be very glitchy and i wonder if that is the reasoning behind doing things differently in TS4. TS3 was/is difficult to play on various types of machines, and to minimize that, gameplay has been left out.
So leaving out diving lots i understand. A native dance, hammocks, native songs, i don't understand how that has been left out.