so theres enchanting, and thats great, but silver weapons and the longhammer have non enchanted effects.
so what if we could take stuff like that (plus more would have to be added of course) and use that as a sort of smithing enchanting. take apart the weapon, learn how it works, then apply that to what your making for extra parts. say you make a dragon bone greatsword, if you had taken apart a silver weapon you could give your sword extra damage against the undead, or knock it down a weight class to swing faster, or do extra damage.
I think Sliver should have gotten it's own weapon category and should have been smithable, could have kept the more damage to undead and been able to have been enchanted at that too. I feel smithing should stay in the series but the items to craft stuff should be really rare, it makes mining pointless when blacksmiths have everything I need to smith awesome stuff. I beliebe Two Worlds 2 had a crafting mechanic just like how you're describing, well, the breaking down part of things anyways and it was really neat to use.
Soul of the Mind key to life's ether, Soul of the lost withdrawn from it's vessel, Let strength be granted so the world might be mended- Maiden in Black