Alphatian Wizards, 3E
by AshtagonJust because rules for something exist, doesn't mean that something has to be shoehorned into every setting. Nearly all (all?) of Mystara's fluff works on the principle that academic study and book-learning is the one true path to learning arcane magic. Of course, the exact physical form of the "book" can vary depending on the culture (cf Ethengar). The one near-exception is the Alphations, but even there it is more a case of genetic predisposition towards magic that is brought out by training -- kind of as if they had a genetic predisposition towards high IQ, and their culture then took to that by sending them all to good colleges.
I'd just drop the class entirely. If pushed, a feat for wizards:
Follower of the Wind
Prerequisite: Must be an arcane caster with at least three spells in your spell books, at least one of which must have the air or electricity descriptor.
Benefit: Choose up to three spells you have in your spell books, one of which must have the air or electricity descriptor.
You no longer need to memorise these spells. Instead, you can cast them spontaneously by sacrificing a spell of the same level that you have memorised. If you have spell slots of the same level which you have not filled with spells, you may sacrifice one of these unused spell slots instead of sacrificing a spell that you have memorised.
Special: You can take this feat multiple times. Each time you do so, choose three additional spells.
Follower of the Flame
Prerequisite: Must be an arcane caster with at least three spells in your spell books, at least one of which must have the fire descriptor.
Benefit: Choose up to three spells you have in your spell books, one of which must have the fire descriptor.
You no longer need to memorise these spells. Instead, you can cast them spontaneously by sacrificing a spell of the same level that you have memorised. If you have spell slots of the same level which you have not filled with spells, you may sacrifice one of these unused spell slots instead of sacrificing a spell that you have memorised.
Special: You can take this feat multiple times. Each time you do so, choose three additional spells.