The more I am looking into the game and try out your updates, the more convinced I am you might be creating THE game of 2017. People love the game, youtubers are picking it up as well, I hope you get the support you need! Good luck, man, you deserve success with it, the idea is great.
Other people have already picked up ideas I also would have suggested like:
Temperature (very hot - need more water; very cold - stored water might freeze, you need a fire to keep you warm, better clothes)
different sharks and NPCs (also friendly)
I will present you my suggestions for these ideas and also other new ones:
Add a bed (can be crafted out of a lot of thatch and some ropes to keep it together, could look more like a pile of thatch than an actual bed. If nights are added you can animate a sun and a moon, perhaps also stars, according to which you know how late it is. For far away future: you could create an even bigger world and you'd have to navigate according to the stars, according to where you travel you could paint maps - literally let the player him/herself make the map according to how long they travel somewhere)
Make surviving a lot harder (when I start playing it's not easy, however if you play smartly you soon enough reach a point where surviving isn't that hard anymore. Add not only different kinds of fishes to eat and catch, but also make the catching a lot harder. Think of some sort of bait, perhaps pieces of raw fish or insects. More seeds would be a great idea but everything should take a way longer time to grow. When you have to survive you can't start growing potatos as it would take months for them to grow. When a day and night circle is added you can let stuff like potatos take up to 5-7 days and palm trees 15-20 days. There should be some variety in the plants growing in general.)
Weather (storms, waves, sun, wind, ... all these natural issues can occur and damage your raft, perhaps even throw you off and you have to swim back while keeping the shark off. The weather could also affect and damage the raft, pillars could crack if you don't repair them on time or a piece of the raft might just break off in general)
Nets capture so much (which is awesome and therefore too easy I think. Perhaps let them catch up to 3 items only, the rest should swim through, and if more than 10 items got through the net could break)
All together your game already improved a lot, it's great! The added chests are very useful, I like that you need a lot of metal for them and that they don't have that much storage room. I think you could in general make a "normal" and "hardcore" mode later on, just different stages of how hard surviving might be.