In cataclysm, one can learn skills by either spamming crafting or by reading books. In reality, you can learn theory by reading and practice things by doing, but in order to get actually good at something, you need to do both.
What if we make it so that there are actually theoretical and practical skills? For example, there’s theoretical electronics and practical electronics. Then make it so that crafts require some amount of both of these skills and one of them can only be learned by practice and one of them can only be learned by reading.
This is mostly a metadata-level change, as no actually new code is required. Basically just rename some skill to clearly reflect that they refer to theoretical knowledge and rename some other skills to refer to practical knowledge. You can not really learn soldering without doing much soldering and you can’t (realistically) learn circuitry without studying theory.