I also think the randomized scroll creation makes creating scrolls in the first place almost completely useless. Crafting is meant to be consistent and reliable, there really shouldn't be randomization in which item you get from any of the combinations. That being said, maybe instead of being able to craft skillbooks at all, you can instead craft an item that makes that character learn one spell that they're capable of learning but haven't yet learnt. A 'Tome of Discovery' or something. This way it would always be worth crafting because you'd learn some spell you don't know, even if it's not a particularly useful one to you. Would encourage making multiple of them. As for scrolls, possibly a good system would be that you turn parchment into a scroll precursor, which you then combine with something related to that element to make it a scroll of that element, which you then use the magic ink and quill on to inscribe with a particular spell. So for example enchanted parchment + shell makes water scroll, which you can inscribe into a scroll of rain. Or enchanted parchment + rock makes earth scroll, which you then inscribe into a scroll of acid dart.
