1. I suggest that it would be nice to have an consumable item dropped by monsters/shops/tavern and using it up allows a character to add a gem socket to the item, providing the item does not already have one.

2. Also you can add value for metal resources because no one is using them. Maybe add some crafting recipes for making items and you will find these recipes in tavern adventures. When you find epic item recipe then you need these resources for crafting it. You can add more resources for example copper, titanium, cloth, maybe flowers etc.. And last idea add value for the witch. It is along with this crafting system. For example this ingredient needs to be boiled for 12 hours, or this needs to be enchanted and it will take 3 days. I hope you get the concept.