One thing I loved about the D&D based games, is that you can scribe a scroll (writing a spell down in your spell book, keeping that spell).

Should this be implemented in Skyrim?

I think it should, but there should be limits. Like you have to meet the requirements to be able to scribe it, and have to pay a certain amount of gold based on the spell's power.

What do you think?

Why the hell not, and while we are at it, wouldn't a bunch of single use arrows be easier to enchant than a permanently ensorcelled plate cuirass?