Abemore, while I acknowledge your point, death, pain and maiming are not valid deterrents in this game. And making it take a few years of study to cast a spell is counter productive to having fun.
But your proposal as valid as it seems on the surface, would mean that everyone who is a caster would have the same spell list.
But in the end as long as the teacher pays something in order to teach the spells, I have no problems, or that the pupil risks loosing skills or other known spells when learning new ones.
AC had a neat system where by the more people who knew the spell the less powerful it was, this was mostly on the big name spells. The result was that on raids or any large high level combat the casters where nothing more then hit point batteries, as any of the melee types would always do more damage then the top casters.
So, while I agree in the get scroll/learn spell is pretty stupid, our first incarnation of the magic system will have something very mush like that, later we will probably migrate to something more effective, but the balance of cause and effect have to be maintained.
