I think tools should be reworked a bit.
Generally, I am going to suggest that there would be 3 versions of tools. From worst to best: Wrought Iron, Bronze, Steel. Mostly this would affect pickaxe that I would like to see as more effective minign tool than any stone axe regardless of its type and quality.
viewtopic.php?f=5&t=32430
In this thread I suggested Metal tools for skinning and butchering. In retrospect it is bit shaggy but like the pickaxe example the would be Iron, Bronze and Steel variants.
Issue with current system is that all formulas count tools qualty directly, thus you can not increase metal tools quality as easily as that of a stone axe. Tools should be given attributes derived of its quality like Armor already has Deflect/Soak/Hit points.