It seems this mod currently suffers from a bug where players are unable to reach three stacks of Fractured Armor.

The way it's supposed to work, Sundering Smash and Staggering Blow will set Fractured Armor to an enemy for 2 turns. If the enemy already suffers from Fractured Armor, it will be replaced with Broken Armor. If the enemy already suffers from Broken Armor, it will be replaced with Sundered Armor.

However, currently if the enemy suffers from Broken Armor, Sundering Smash and Staggering Blow will replace this with Fractured Armor, removing a stack of the debuff instead of adding one. This also prevents players from receiving the Inspired buff and the Craft Weapon skill that uses it.

The rest of the mod seems to function properly, however. Until Halaene revisits this mod and looks into the bug, we'll have to live with Blacksmith being a very competent tanky melee support without the ability to craft weapons.