Love this concept. I'd love to build on that by going back to a mix of learning by doing and learning by reading. You could separate out the books by tech level and have a minimum level required to unlock crafting of items and then the quality progression in that space could be a mix of crafting experience and additional books. If you nerfed trader rewards and tied the book probability of higher tiered items to gamestages, you could end up with a really nice system.