Leather and bark armor currently isn’t very useful – it’s really easy to mine fairly safely and go straight for iron. I’d like to see leather armor and iron armor be able to be combined into Plate Armor (leather padding under iron armor). A wooden shield (+2, made from logs), as an upgrade to the bark shield could also be a required component for a tower shield (wood shield + iron shield). More items for the waist (perhaps an Iron Fauld?) would be cool.
Jewelry crafting for the ring / neck slots would also be fun and allow players to fulfill the treasure requirement without killing; you could add rare gems to mining. (Perhaps even let jewelry be enchanted?)
A leather slingshot could allow smooth stones to be used like arrows.
I’d also love to see a “special” boat, similar to the bull boat, but that would take you to a more advanced / difficult realm – ones with tougher monsters, better treasures, and possibly rarer materials to make even more interesting things.
Add some uses for shale. Allow Shale + Large Rock to make Smooth Rock, or perhaps 5 shale to create a stepping stones tile (similar to cobblestone, but shale-colored). Also, adding marble would be awesome!
I love the game. Keep up the great work!