Since the hit points in OL are treated as an abstract measure of being able to project your presence onto the battlefield, I thought it might be less confusing for new players to use terms which better reflect that. I would rename “hit points” to “endurance”, “damage” would become “exhaustion”, and “lethal damage” simply “damage”. This way, a successful attack wouldn’t “damage” and opponent, but “exhaust” them (unless a d20 exploded). I would just track the exhaustion and damage as separate quantities and introduce a rule that if sum of exhaustion and damage reaches the endurance, a character falls unconscious. Of course, the sum can never exceed the endurance, and damage takes precedence over exhaustion (meaning: if endurance is 20, damage is 5, exhaustion is 15, and 5 damage is dealt, then the character has 10 damage and 10 exhaustion).
I think this would better bring across the idea of what hit points mean in OL. What do you think?