I have an alternate suggestion, though I'm not sure it's possible to code easily. Make it a blend of the ff1 + ff8 system.
Let there be a certain cap on how many stores of each spell a person can have, and let those spells be replenished after battle. They would either be restored outside of battle or with resting, either would be fine. If the cap is low enough this still allows for there to be a purpose to using the draw ability in battle. (I'm imagining either the ff1 9 max cap or perhaps even 5 if spells are restored outside of battle). The caps could increase either linked to level (ie lvl at <10 only able to store 1-2 lvl 1 spells, lvl <20 2-3 lvl 1, 1-2 lvl 2, etc.) or linked to drawing certain spells (ie drawing thundara grants a cast of thundara and an extra cast of thunder). The spell bonuses would obviously be adjusted to be proportional. This may require disabling the trading magic function to make any sense.
I'm somewhat unfamiliar with how ff8 handles spell consumption, but it would add a bit of strategy if using one of your only spells reduced the associated stat drastically.