I've been playing about 4 to 5 months on two servers.
Here are my ideas:
1) Historically accurate neolithic bone axes, shovels, and knives. Ironically, the neolithic bone shovels look *exactly* like the existing shovels in the game. The axes look similar. This would be a white texture for the blade and possibly a lower durability than flint. It would also make "skyworld" playthroughs easier (giving your game more videos on Youtube) as bone tools would be renewable.
2) Accurate creation of clay by putting dirt in water and letting the clay settle out over time. I can see a "firepit" mechanism to start. Dig a hole, fill it with water, toss in X dirt, wait 24 hours, get a piece of clay on the bottom of the water block.
3) Adding some kind of blower mechanism to bloomeries or firepits. This would make them burn hotter. It's a real thing in the real world. You might limit this to certain classes since only certain cultures developed it.
4) Create a new water block. Either make it so you can't pick the block up with a bucket, or make the bucket remove this kind of water block when you fill a bucket from it. Make buckets place this kind of water by default. The magical water source blocks from tobg are destructive to immersion and don't fit the "simulation" nature of the rest of the game. Using a bucket on a block should pick this block up.
5) Add a jonas device that *creates* source water blocks.
6) Make chests immune to flame or make firewood flammable by default. It's silly that chests burn but the firewood next to the firepit doesn't burn. It's really painful to have your chests burn tho.
7) Change drifter drops of 1 fiber to be 1 to 2 fibers... Doesn't have to be 50/50, could be 2/3 one fiber, 1/3 two fibers. But it does give a little dopamine "hit".
8 ) Increase the time cherries and peaches are ripe when in multi-player. They may literally only be ripe from 1am to 7am. I suggest making it 24 hours so players have one real day to harvest.
9) Since you have rammed dirt and packed dirt, change ordinary dirt so it won't stack more than 2 high when placed by players.
I have one more that's heavier weight but I can't remember it right now, I'll have to add it when I remember it.