Yeah, Red51 noted there'll be a 'one world ocean' biome with islands behaving like varying types of continents of all sizes.... Big, small, and all sorts. With this in mind I guess Red51's concept of how boats should behave may actually be put into practice now. If he wants to explain it I'll leave it for him because I can't recall if it was a private or public concept. Boats will behave differently.
As for boats......
Various boats, including small rowboats and big sailing ships (as well as some modern vessels). Bigger vessels will be customizable to a certain degree.
It has me curious what sort of 'modern' vessels we shall gain. If we get something along the lines of an S.S Nomadic type boat I'd be happy. Its the right size to go through big rivers, a place to live, and a place to store your goods. Even hold crafting stations. If it has any built in then that be even better. If its modern fishing boats, tug boats or whatever then that would be fine. I hope Red51 gets access to a good source of boats.
Red, Will it be possible to craft windmills and water mills for generating electricity and processing grain into flour, for example?
I know you want to hear from Red51, and you shall. I just want to note this is planned (or was planned in Java). Windmills would be cool, as with river types. They were supposed to come with the electricity update for Java. After the basics are applied to Unity version I'm certain we'll obtain these.