Random though:
Personally, I liked the magic system in NetHack. Wizards could do so many cool things because they could read spellbooks to get new powers. But then they need to have enough knowlege in that particular area to even learn the spell in the first place. It has a sort of simplicity in it that I like. (plus the fact that those spellbooks were so hard to find, buy, or iidentify...
Anyway, having spellbooks that teach specific spells sounds really good for me.
One other random thought: Thief vs. Wizard
Theif: I have a skill that lets me steal items from another persons inventory.
Wizard: Oh yeah! I can summon bolts of energy to strike down my enemies... as long as I hold these little glyph things.
Thief: *steals the wizards glyphs* Yoink!
Wizard: ...
Moral of the story: Skills are better than items, because nobody can steal your skills.