After some thought, and after looking at some other comments, I agree that more trees would be nice. Specifically fruit trees. Also, larger gardens would be a nice option, as well as a harpoon to stab into the shark and either pull it to you to kill it, or have it pull you across the ocean to new settings.
These new settings could have different kinds of fish, different amounts of different materials, or it could even be an island.
In regards to the island idea, after a night or two, a storm could happen, forcing the player to either return to the safety of their current raft, or risk being washed out to sea without it and having to start all over. If you implement all of these features, using the harpoon on the shark could also offer the slim chance of finding your old rafts, if you had lost them.