One idea is perhaps the Summoner idea of levelling up, each character has a set of abilities, they learn more as they get more expirianced (like the warrior, forgot his name, in the late stages manages to learn some white magic), whenever you level up, you get 2-5 attribute points (depends how generous youre feeling) and your HP/MP maxes out. Now, the abilites you learn depend on how you attribute the points, the only restriction being that they can only go up to your current overall level.

Say that as a default, i had three points for white magic, that is what allows me to use Close Wounds (which i assume is heal right?), if i wanted the next white ability which may be, oh, i dunno, regeneration so that HP heal over a period of time, i might have to put one or two into white.

At the same time, next time i level up, i might also have one fire point, meaning that i start off with a low level fire attack, like fire arrow, but i can put more points in to get a higher ability, you can bring these in at any time and they would be different for each character, ie, Sarah would eventually have fire, ice, air (including at higher levels,lightening), earth or dark spells to call on,darkness only as she gets more advanced and her body can take it. At the same time, the option to level up an attack ability like melee or archery may also be in play. For the spell abilities, each character would need to know the next unlockable ability qand how many stat points that would require, melee or archery would mean higer attack in those areas.

I dunno, not telling you how to run this.

If no one else wants the med packs, put them on my list also, but only if no one else wants them.