I agree we should have a reason to level the blacksmith up to 10. I disagree with the idea of adding more resources, since it's a blacksmith, the bonus should be related to artifacts. Maybe something like this: With a level 10 blacksmith, permanent artifacts lose durability 10% slower. Or a way to repair a small portion of damage but only if the blacksmith is level 10.

Also maybe the level of the crafted artifacts should be tied to the level of the blacksmith. (Only the Poisoned Arrows right now require a blacksmith of level 3)

Another thing, maybe only with a level 10 blacksmith, it would possible to salvage some raw materials from existing artifacts.