Personally, I really liked that Lightsabers were hella dangerous to the wielder in WEG's edition of SWRPG (or at least the 2nd Ed did, which is the only edition I had substantial experience with). Lightsabers had a special effect that injured the wielder if an attack missed the difficulty by 10 or more. The weapon's base difficulty was also a 20, which was 5-10 higher than other melee weapons in the game. I don't want to get into the details (they're pretty bizarre by today's game rule standards), but it meant that lightsabers were substantially harder to use than other melee weapons.
These qualities made 'sabers pretty unappealing weapons, unless you were had substantial training and/or were a Jedi/force user with the Lightsaber Combat force power. To bring this back to the thread, I would make the following changes to EotE:
#1: Add the Challenging weapon quality to the game
CHALLENGING X [PASSIVE]
Challenging weapons are more difficult for untrainted characters to wield in combat. If the weapon has more ranks in Challenging than the attacker has ranks in the weapon's associated combat skill, then the difficulty of checks to use the weapon is upgraded a number of times equal to the difference between the weapons Challenging rating and the wielder's weapon skill ranks. If a characer's ranks in the relevant combat skill exceed the weapon's Challenging rating, then the Challenging quality has no effect.
#2: Give Lightsabers Challenging 2
#3: Add the following text to the lightsaber's descriptive text:
Because the energy blade produces no resistance and has virtually no weight, it is very dangerous for beginers to use, and those without any formal training are as dangrous to themselves as to their opponents (straight up copied from WEG's SWRPG 2nd ed, R&E, pg 228). Game Masters can spend [Despair] to inflict a critical wound on the wielder of the lightsaber.
Without a connetion to the force, it is difficult for a character to intuit the orientation of the lightsaber's weightless energy blade. Despite being a melee weapon, the base difficulty to use a lightsaber is "Hard" (PPP) for characters without FR 1 or greater.
With these changes, 'sabers are now nasty weapons untrained, and the Challenging quality provides a way to generate the [Despair] needed to activate the lightsaber's special ability. The Lightsaber skill is now invaluable because it reduces the threat of self injury from the Lightsaber's Challenging quality.
Alternative #1: Amend text in #3's text above, first bullet point to require the roll to also be a miss.
Alternative #2: Just make the lightsaber's base difficulty "Hard" unconditionally.
Alternative #3: When making an attack with a lightsaber, a character may add a number of force dice to the roll equal to the smaller number of ranks he has in either his [effective*] FR or Lightsaber skill. Each lightside point may be treated as either a success or advantage at the character's discretion.
*Remember, characters that have active ongoing effects from their force powers have their effective FR reduced by the number of force dice committed to maintain the ongoing effects.
The term "Effective FR" is not used in the book, and I'm using it here as shorthand for "The number of force dice a character could roll to activate a force power this round", or "FR - Force dice committed to ongoing effect maintenance".
Anyway, just a few ideas. Overall, Alt #3 is the simplest, but I really like the flavor added by the other changes I proposed above.