Loving this game! So, suggestions...
Wondering through the woods I thought it would be good if there was animals, like wolves which gives a reason to equip a weapon. So, perhaps combat.
Seasons would be interesting. Different weathers.
Hiring people to work for you could be fun, for example travelling far for unique materials, instead of yourself. Or running shops in other places. Perhaps taking on apprentices? Also, if there was combat, hiring bodyguards.
Making armour, however I have a feeling this is already planned (armour is on the scarecrow)
Reasons for travelling. I loved exploring, but other than finding crystals and unfinished content there was not much I got out of it. Perhaps unique metals or blueprints for weapons.
Other blacksmiths! Compete with them, share information and products. Rivals or friend. Perhaps they wish to sabotage your business!
Unique commissions from special NPC's where you must gather special materials, and have a long time to do it. Going on adventures to create the ultimate weapon, for a price of course!
Bulk purchases! A large amount of weapons over a long period of time, but I could see this becoming a grind to complete...
Deeper mining! Explore deeper, perhaps even dungeons with pre-made ancient weapons, but dangerous to get!
Better optimisation overall. My PC CAN handle the game, but not very well.
More customisation of weaponry, perhaps special decorations make of jewels?
Factions! Raise loyalty with factions and in turn you get extra customers, like working for a king supplying his army.
Fame! As your weapons are used by heroes successfully increase your fame! A marker of your progress other than money. Perhaps makes you more willing to increase the quality of products otherwise you get bad reputation.
Sorry for the long list, and thank you for the game! I have been loving it, and you have got me interested in a genre I seem of have neglected. Good luck for the future!