So I'm not the most experienced person with the crafting systems, but in the process of messing around with smithing something somewhat incongruous has come to my attention:
The DC and materials required for making bronze are both higher than they would be for copper--the DC to make a bronze weapon is 3 higher than copper, and the smelting process for bronze first requires smelting copper and then smelting it at a higher DC with tin to forge the alloy.
However, bronze weapons in particular are straight worse than copper. The penalties for both are the same, but copper at least has a bonus. Bronze has absolutely nothing going for it. This isn't to argue that bronze should be amazing, simply that it should have some benefit above its copper equivalents.
This seems to be only limited to weapons, I will say. Bronze armor is slightly better than copper.