Here, any wizard of any alignment can claim citizenship. Anyone casting a spell to harm another receives an immediate backlash in kind. Many spells fail unless they're done for the greatest real good of the greatest number. Conjuration-summonings done for a good purpose have the best possible result, while those for a bad purpose result in the summoned creature being uncontrolled. Divinations only work for groups of four or more folks seeking the greatest good for the greatest number of decent creatures.
Necromancy only works for the common good.
Animated dead turn on the caster, and death magic turns back on the caster. Wild mages lose two levels, and no surge is possible. Elemental magic works at double effect for those aligned like the plane, fails for evils and chaotics, and works normally for everyone else. It seems unlikely that spell keys would be able to overcome many of these problems. Wizardly spell keys are material from the plane, bounded by a geometric shape, and symbolic of the desired effect.