If I'm reading those rules right, you would not be able to craft a scroll for a spell you do not already know, and you can't make a spellbook for a spell which you do not have a scroll for. With those rules combined, you could only make spellbooks for spells you already know (unless you find a scroll for a new spell). By definition, you don't need spellbooks for spells you already know.
I disagree with removing higher-level skillbooks to make the crafting skill useful. It is already pretty useful, but it should not be mandatory.
The goal to let you pick the spell you want to make a scroll or book for is good, though. Skillbooks from quest rewards is also a good idea.
