I gave clerics some love, so now I want to follow it up with some Wizard-love, haha!
Magic Users memorize spells the same as usual, but can spontaneously swap out an already memorized spell for anything in their spellbook up to once per point of Intelligence modifier. (e.g. If you have an Intelligence of 16, you have a +2 modifier so you could "freecast" 2 spells per day.)
Since intelligence represents "memory", I think this might be a great way to encourage situations where Magic Users can use a wider variety of spells in situations. The normal memorization system tends to encourage MUs to only select spells with really "wide" utility, like Invisibility/Sleep/Grease/Web/etc, so we end up seeing a lot of repetition!
Magic Users memorize spells the same as usual, but can choose an amount of spells equal to their intelligence modifier to be swapped spontaneously as needed. Every time the Magic User attained a new level, he/she could change out a single spell in the Spontaneous Pool.(I totally ripped this off from a feat in some 3.5 splat book)
If the same applied to Clerics too, a Cleric with 13-15 Int(+1) could choose Cure Light Wounds as his/her spell-of-choice and function similarly to a 3.X D&D Cleric.
Any thoughts? If I demo'd one of these ideas with the AD&D game, which one would be preferable? I think Iris has a pretty solid intelligence, so both her and Esraminh could take advantage of this. I could possibly even try one for wizards and one for clerics, but the more complicated I make the systems, the harder it is to remember it all.
Yet at the same time, Wizard and Cleric are both so iconic and important to the game that giving them their own modifications would be totally reasonable!