Conquest of the Horde

So, I'm just looking through WoWWiki and my RPG books to see what exactly the difference was between mages, wizards, and sorcerers. this is what I came to understand;

Mages: Use a spell book, as well as the arcane. Prepare spells.

Wizards: Prepare spells; IE, use a spell book, but 'they do not channel arcane power, instead use their vast knowledge of otherworldly forces to harness the energies to their will.' to quote the RPG.

Sorcerer: They don't prepare spells, and they don't use a spell book; Instead, they use their own bodies as a conduit, and use trial and error to see how their spells work. It's a much more natural approach (as natural as arcane can be at least).

This leaves me with a few questions however.

- If wizards don't use the arcane, what do they use?

- Do mages and wizards really need spell books to cast their spells? If so, then that's a pretty big deal in the mage community.

- Hedge Mages are said to use Witchbane to draw out evil... What evil is it they're drawing out exactly? An internal evil, or some form of evil from other beings? If it's other beings -why- are they drawing it out?

Sorcerers and Wizards are remnants from 1st edition Warcraft d20 (where they were borrowed classes from D&D), they don't exist in the 2nd edition and likely don't exist within the context of Warcraft's lore.