Disclaimer: The last time I played SWRPG was back in '97, so I take no responsibility blah blah red stapler blah.
The original [2nd ed] SWRPG handled lightsabers as a melee weapon doing 5 dice [5d6] of damage, same as a blaster rifle, but bypassing any armor the victim was wearing. What made them deadly in the system was [aside from their ability to deflect laser shots] how easy it was to hit someone in melee, as compared to a ranged attack -- 'course if you want to slice the bad guy with a lightsaber, you'll probably be in point blank range anyhow
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Now, that 5d6 wasn't HP damage either, since SWRPG didn't have hitpoints to begin with [it used a variant of the Paranoia combat / damage system, interestingly enough]; basically the attacker rolled 5d6 and if the victim couldn't roll higher using his strength roll [Xd6+modifiers, attributes generally don't go above 2d6+1, and you could use XP / force points to boost the roll], he'd become stunned / wounded / incapacitated / dead depending on how much he missed the damage roll by. If you were already in a condition, you'd use that as a basis. (so a hit that'd make you go from normal to wounded would kill you if you were wounded already and incapacitate you if you were stunned)
With lightsabers you also had the option of severing a limb instead of killing an enemy (knocking the enemy unconscious) which was how the 'Light' jedi preferred to defeat their enemies. Light saber wounds also didn't worsen over time, compared to pretty much anything else. (instant cauterizing, coming up!)
Oh yeah, this was balanced out by making lightsabers rare as 'eck and having lightsaber combat as a 'trained' skill. [ie. you need a trainer to improve] It was the only combat skill a character couldn't improve on their own IIRC. There were also rather heavy rules associated with acquiring / using one, etc etc., but we all know that.
-- Z.