Maybe you could give stats to various materials. So merchantmade items of that
material could have +1 or +2 of that stat. And for critical successes on make
armour you could have a higher bonus. That way people could use a wider range
of equipment and sort of have it tailormade for their needs. stats im thinking
being resists, stats ( str, dex, etc ) hit, dam, avoid etc.. maybe regens too.