Hello!
I'd like to focus your attention on ways to improve the appeal of lakes and rivers, to make water tiles more useful and not just a spot to collect a few resources.
1st. Stilt Houses. It would be neat if you could build some small structures on shallow water (or swamps). The easiest option would be to just add a custom house (like a TimberHouse-sized building) that can only be built in shallow water.
The better option, but a bit harder to implement, would be to allow any small building to be built on a raised wooden structure in the water. This would mean having a wooden structure (let's call it SUPPORT) that needs to be built on water, which then allows you to get on top of and construct a building on it.
Let's say Supports are 2x2. You want to build a Timber House on water, so you have to build a 6x6 square made of 2x2 supports, plus a little extra by the door to be able to access it. There should be a way to build some kind of ramp or stairs, to allow you to carry lifted items to and from said supports (no climbing).
This kind of system would allow to build some kind of "fisherman's village" entirely on water. Personally I would only allow some structures to be built on said supports: no bricks (ovens, smelters...), no large houses (anything bigger than a Stonestead. Or even a TimberHouse), no tar kilns or mine holes, no palisades or brick walls. I would allow small structures, like cisterns, drying rack, Log Cabins and Timber Houses, Coops and Hutch...
2nd. If Stilt houses become a thing, with the support system especially, some kind of defence would be needed. Two special kinds of water-fences would be required: a weak fence-style structure, and a stronger palisade-like "dam". This second kind would also require a special water-siege weapon, or to allow people to use siege weapons on rafts (which would be awesome).
3rd. Water farms. Even without a real on-water village, people on shorelines could benefit from this kind of farms. There should be multiple kinds, depending on what you're farming:
- Fish farms. Something between fishing nets and chicken coops. You drop them in deep waters, put a few fishes of the same kind inside, and fill it with fodder. After a while, fishes spawn eggs (caviar!) which will turn into more fishes soon enough. This would allow players to farm a specific kind of fish, and improve its quality.
- Mussel farms. Build directly in shallow waters, would generate mussels until full. Could work similar to a compost bin, where you put stuff inside, which will turn into mussels after a while, allowing for better quality.
- Algae farms. Built directly in shallow waters, would allow you to plant different kinds of algae (we only have kelp right now), for first aid and food. Algae should work like crops.
- Crabs farm. Built directly in shallow waters, would work similar to chicken coops, but with crabs. Put fodder in (maybe fish?) and a few grown crabs, and they multiply. This would require a safer way to handle ((or at least to kill) crabs, or it would be super bad for players.
4th. Buoys. Simply a trail system for boats. To prevent the waters to become impossible to cross, buoys shouldn't be an obstacle (unlike road signs), so that boats can go through it instead of bump into it. You would need some kind of boat to use them. Boat Building should be a prerequisite to place them.
5th. More aquatic animals, and aquatic only creatures. We already have animals living by the water, like ducks, seals, beavers and so on. It would be neat to have aquatic-only animals too (other than the cave-anglerfish).
Critters, like ducks, could be turtles, rays, jellyfish (requiring gloves to pick safely?), and octopodes.
Docile animals could be stuff like dolphins, manatee, manta rays, even whales.
Hostile animals could be water snakes, crocodiles (in swamps too?), or sharks.
Given the amount of large bodies of water already present in the map, including large areas of shallow water, I believe this kind of addition would greatly improve the gameplay extending the play-style options a player has.
Any suggestion or contribution will be gladly accepted.