The lite-rpg is supposed to have easy to track progression and easy to understand requirements to progress. It is important to remember that actual rpgs are carefully balanced to make every path theoretically equal, but stories don't need this balance outside of making valid parties and keeping variety in the world.
Skills can be limited to a certain number (easier on you), unlimited (easy to botch but more rewarding when done right), stay static (block lv 1 -> block lv 2), expand in evolution (Block (blocks attack you receive) -> Defend (block any attack)), or transform (block (can block self) -> defend (can only block other)). Decide on resources (health, mana, skill points, gold points, stamina, class points, specialized mana types (fire, ice, wind, etc.), mental energy, soul power, etc.)
Classes can be dealt with in five way: unofficially (he knows heal), skill based (he knows the healer skill that grants him better healing), Synergy based (he knows anatomy, giving a boost to healing, muscle training, and critical hit chance/damage), Statically (healer lv1->healer lv2), evolution (medic->healer)
If you are aiming for a comedic tone have certain mechanics just not make sense in real life, otherwise don't make your skills too concrete. If the world is affected, think about how your system would impact society. Maybe have economies be built by crafting classer guilds while kings grant bonuses to their subordinates.
The most important thing is that goals should be set by the character for a power, reach that power, and than have that power show. Also, under no circumstances should the system assign a mandatory quest with system assigned penalties. While you can make "Survive" a mandatory quest, you cannot have "Confess or Die" be a quest. It undermines their control.