World of Origin's Age of Renewal
a) The PHB wizard is a Prestige Class instead of a Class.
b) A PC/NPC can only become a wizard by being accepted as an apprentice by a full-fledged wizard, and completing it’s training under the wizard (1d6 years).
c) Wizards will never waste their time training anything less than an Arcane Spellcaster who already a basic grasp on arcane magic. Often a wizard will select these candates for wizardry from the best (or favored) amongst the Arcane Spellcaster “lackeys” he has personally taught.
d) Before granting a candidate apprenticeship the wizard will most likely give her a test or quest of some sort to measure her worth and abilities (see Test-Based Prerequisites above).