I have three suggestions that I would like to share, and hopefully influence the game's progress in a minor (very minor) way.
-Different Types of Hammers
What I'm thinking for different types of hammers is that making a different hammer affects the material (and by extension the weight and material needed to hold up floors and possibly walls) the structures are made of. This would in turn affect their strength and resistance to sharks, seasons as other people have said, and something I'll mention next.
-Hostile NPCs and Advanced Combat
This may sound unrealistic (and trust me, I know it is) but it would be neat to have other, hostile (and possibly themed) Rafts come your way where they will use their hook or something new added to bring their Raft closer to yours to attack you. They could also loot and grief your ship. Going along with the themed idea, maybe some could have rare loot like new materials or extra food/scrap depending on their theme and maybe, just maybe, a rare shark tamer.
-Sanity or other Stats that would matter in a Stranded At Sea Situation with No one around
Lengthy title eh? Anyways, as the title says, a Sanity or other trait meter would be added in addition to the health, hunger, and thirst meters. Although it is quite self-explanatory and a bit too close of an idea to Don't Starve, it could effect other meters as well, like faster hunger and or thirst, slow damage, impaired or hallucinogenic vision, etc. This could also be a temperature meter, which would affect other stats as I've said with the Sanity meter.
Thank you for reading these suggestions by me
-S