One of the greatest issues I have with the game is lack of content past a certain point. One of these areas is mining. Having done some research on native minerals of the greater region Haven is set in I have some additions and skill suggestions.
First off there should be more minerals.
Platinum, Garnet, Jasper, Amber, Azurite...
Some of these have been suggested but it's not just about new deposits. We also need new skills.
Gemcutting and Engineering,
Gemcutting would allow us to shape the gems we find into new types of jewelry. There are still many types not included in the game such as talismanic rings, crests, mantles, crowns, scepters, orbs...
Engineering should be added to make supports for lower level mining. Mining in this era was not easy and going deeper was usually deadly.
Obviously new minerals and gems opens up new equipment such as:
Gemcutters tools & table
Miners pan and sieve
This also opens the possibilities of new curios to be added.
The more content we add and skills needed to be raised the longer it takes to master things. As it stands now most things are underway in a month with some level of skill. I believe theses addition may allow us to extend content longer.