Lots of people are complaining about smithing, rightfully so, since it's pretty broken and lets players create weapons to sell for tens of thousands very easily. Problem is not however the crafting system itself. While the crafting system does have its issues the main problem which lets the previous thing happen is the core calculations for weapon (and armour) prices in bannerlord. And you cannot fix smithing without addressing this. The problems are as follows
The price of weapons are calculated primarily on damage stats as it's set up in vanilla. The materials used for the weapon and its crafting difficulty play almost no role in determining its price (they do, but so little it's not even noticeable). Raw damage statistics is what make a weapon cost go up. The problem is also that the price increase is exponential, not linear, and it's exponential to a ridiculous degree. What this means is that it will always be the most profitable to craft a weapon which maximises damage stat and nothing else.
This of course leads to the obvious problem that a low grade two-handed weapon will turn out way more profitable than a high grade one-handed weapon because the two-handed weapon has more raw damage. And because the price increase is exponential it will be worth way more. So you end up with an economy that has a ridiculous setup where a simple two-handed axe will cost 10x that of a finely decorated, crafted and gilded sword. Which obviously doesn't make any sense from a realism point of view. But it doesn't make sense from the game's point of view either because it means that there's no reason to craft high tier weapons when lower tier ones can be worth way more and are way easier to make. You cannot fix the issue in crafting without addressing this.
Solution is twofold. One is to decrease the price modifier, so that the change in weapon price isn't nearly as exponential as it is now. And the second, more important thing, is to reduce the impact on weapon price based on damage, and instead have the price be calculated primarily on materials used and crafting difficulty. This will mean that crafting a fine golden sword will in fact get you a very expensive weapon, and not one which costs several times less in comparison to a crude blade on a long stick.
Obviously I also think that the price modifier needs to be severely decreased for armour too. Why the hell does one suit of armour cost more than a goddamn castle? It makes no sense.
Anyway the solution above will fix the core issue with crafting, but it won't address some of the other issues crafting has so I will propose solutions for them too.
Unlock system is very bad. Pretty much everyone agrees with this, but how to fix it is another matter. In my personal opinion the best way to fix it is to tie unlocking an entire tier of weapons to your smithing skill. So for example 25 smithing skill unlocks all tier 2 options, 50 skill unlocks tier 3, 100 skill for tier 4 and 150 skill for tier 5. As an example, doesn't have to be those exact values.
The crafting XP needs to be reworked as well. It's as far as I understand pretty much directly influenced by the price of the weapon you create. However without creating a bunch of overpowered weapons worth above 100k leveling smithing is very hard, so the XP gain should be rebalanced imo. Perks should also be completely reworked and stuff like being able to create fine and masterwork weapons should be an automatic unlock.
And lastly I think that there isn't a rough enough penalty for smithing weapons you don't have the skill for. As it is now you can craft a piece which has 150 difficulty when you have 0 smithing and the only downside is that it loses stats. Crafting weapons above your level should instead have a chance to fail which increases drastically with how many levels you are away from it. And I think that being under a specific amount of levels needed to craft a weapon (as an example, say 50) should have a 100% chance of failing.
Anyway those are my thoughts on how to fix crafting, and also fix weapon and armour economy.
The price of weapons are calculated primarily on damage stats as it's set up in vanilla. The materials used for the weapon and its crafting difficulty play almost no role in determining its price (they do, but so little it's not even noticeable). Raw damage statistics is what make a weapon cost go up. The problem is also that the price increase is exponential, not linear, and it's exponential to a ridiculous degree. What this means is that it will always be the most profitable to craft a weapon which maximises damage stat and nothing else.
This of course leads to the obvious problem that a low grade two-handed weapon will turn out way more profitable than a high grade one-handed weapon because the two-handed weapon has more raw damage. And because the price increase is exponential it will be worth way more. So you end up with an economy that has a ridiculous setup where a simple two-handed axe will cost 10x that of a finely decorated, crafted and gilded sword. Which obviously doesn't make any sense from a realism point of view. But it doesn't make sense from the game's point of view either because it means that there's no reason to craft high tier weapons when lower tier ones can be worth way more and are way easier to make. You cannot fix the issue in crafting without addressing this.
Solution is twofold. One is to decrease the price modifier, so that the change in weapon price isn't nearly as exponential as it is now. And the second, more important thing, is to reduce the impact on weapon price based on damage, and instead have the price be calculated primarily on materials used and crafting difficulty. This will mean that crafting a fine golden sword will in fact get you a very expensive weapon, and not one which costs several times less in comparison to a crude blade on a long stick.
Obviously I also think that the price modifier needs to be severely decreased for armour too. Why the hell does one suit of armour cost more than a goddamn castle? It makes no sense.
Anyway the solution above will fix the core issue with crafting, but it won't address some of the other issues crafting has so I will propose solutions for them too.
Unlock system is very bad. Pretty much everyone agrees with this, but how to fix it is another matter. In my personal opinion the best way to fix it is to tie unlocking an entire tier of weapons to your smithing skill. So for example 25 smithing skill unlocks all tier 2 options, 50 skill unlocks tier 3, 100 skill for tier 4 and 150 skill for tier 5. As an example, doesn't have to be those exact values.
The crafting XP needs to be reworked as well. It's as far as I understand pretty much directly influenced by the price of the weapon you create. However without creating a bunch of overpowered weapons worth above 100k leveling smithing is very hard, so the XP gain should be rebalanced imo. Perks should also be completely reworked and stuff like being able to create fine and masterwork weapons should be an automatic unlock.
And lastly I think that there isn't a rough enough penalty for smithing weapons you don't have the skill for. As it is now you can craft a piece which has 150 difficulty when you have 0 smithing and the only downside is that it loses stats. Crafting weapons above your level should instead have a chance to fail which increases drastically with how many levels you are away from it. And I think that being under a specific amount of levels needed to craft a weapon (as an example, say 50) should have a 100% chance of failing.
Anyway those are my thoughts on how to fix crafting, and also fix weapon and armour economy.