An idea, inspired by the Final Fantasy "job system"

[CaelCyndar1993]

This could actually lead to a chain of ideas, all based off of Final Fantasy systems. Some things would need to be adapted of course.

FFT: XP and CP are earned seperately. CP pays for class abilities, XP levels up. When enough levels are reached in a given class, new classes become available.

FFX: 1 CP is gained every time you level up. A CP is used to move around a grid of abilities, and abilities are learned by paying in GP.

FFX-2: Every creature defeated awards 1 or more CP. Each ability has a set amount of CP required to learn it. The player decides which ability the CP goes towards, and learned abilities unlock new abilities. New classes are unlocked by 'buying' them.

FFXII: 1 or more CP is awarded everytime a creature is defeated. CP is payed to learn abilities. Abilities are arranged on a board, and an ability can only be learned when an adjacent ability is learned.

FFTA: Abilities are learned through weapons, but can only be used when the weapon is equipped untill the ability is mastered. Each ecounter awards CP. When enough CP is reached, the ability is mastered. New classes are available when enough abilities are learned.