@LordOfBones
Surcounts and kilts would be awesome, along with cloth bracers and boots beyond level 7...
I think the armors should still be able to get other traits other their primary, though, for hybrid builds.
@Jei
You understood it perfectly

Free Tenebrium ores and slabs are as common as, well, I don't think there is anything more common than Tenebrium in the game... maybe empty bottles and cups. Even if your weapon is not originally made of Tenebrium, you can upgrade it anytime (except for staves) if you have a person with skills in blacksmithing. You can't remove Tenebrium.