I'm absolutely, 100% sure that these will take a long time to implement and probably will not make it in, if at all, within the next half a year, but it's worth suggesting these anyways. Gives poor Jorb and Loftar that much more to think on.
I. Mines connected to the worldmap.
The way I currently understand it, mines are their own pocket dimension. If you had two right next to each other, they would not display the other ladder inside the mine. How sweet would it be if they did though? Tunnels criss-crossing the world, underground roadways, the tingling sense of exploration as you tunnel into a long-ago abandoned mine chamber. It would add a lot to how player diplomatics would work, what with organizing which mineshafts belong to which settlement, tunnel gaurds and gaurdposts, underground invasions.
II. Trenches.
Currently, you can only dig up a chunk of clay once. Why? Surely there is more under it? What I propose here is that one could dig several times in a spot before it gets too deep to walk across (Obviously, some means for players to not get trapped is necessary). One could use several chunks of clay to fill in the gap, which could then be redug, or build a bridge segment to forever cross it. Perhaps the ability to use several buckets worth of water to fill a single tile with water, requiring would-be sappers and invaders to bail out the ditch area first. It would certainly add a lot to player security devices, and it's easily reversible, making it hard to permanently trap a character.
III. Water slowdowns and bridges.
Currently, our characters are Micheal Felps in how they tear on through swamps and water at running speed. I suggest swamps should slow us to a crawl, and bodies of water should slow us to a walk. To circumvent this, one would build bridges. Per tile of bridge, I would suggest a cost of 1 block ( as the support) and 2 planks. It could count as dirt for the purpose of wagon travel, and would make a nice addition to transportation systems, as currently one must pave around the entirety of a swamp or lake to make a road for wagons.
Less huge suggestions
I. Metal shields
Why the hell are people in plate still using some planks coated in leather? I'd think steel shields are easily possible, and maybe wrought iron. It should improve chances of blocking, and each tier up should have a respectively larger cost of harder to get materials, and the actual graphic of the shield would probably be larger.
II. Crossbows
Ridiculously slow armor punching beasts. IIRC, historically, a crossbow string would be some dried/cooked sinews of an animal. Perhaps an item that would be harvestable from corpses exclusively after getting a new crossbow skill. I'd imagine that carving around to extract the muscles would damage the good meat cuts, meaning that it's a choice between the food and the sinews. To balance it a bit beyond just the inconvenience of slow reload, perhaps the sinews should away after a time?