I agree with most of the sentences above. But from my side - I like this game.
I have spotted few bugs. For example infinite water supply (inventory) after loading the game, or duplicates of my bed. I like the physics here except this always-one-boat. Also my oil turned brown from black one.
I don't know much boat-builders and I haven't played minecraft, so this is a bit new to me.
What to expand/ do more?
For sure add some not-cubic shapes. Just for making smooth boats. That should decrease the friction. You could create those pieces in a special workshop building.
Another choice should go for some talks with people around. I don't know if anybody is talking more than a few words.