So here's a question to TalosX.
Would you apply the same gimping penalty to an ancient Sith Sword when using Parry or Reflect? Said weapons were said to be just as durable as ligthsabers several thousand years ago thanks to the Sith alchemical techniques used in their forging, even centuries if not millennia after their creation.
Would you apply that same penalty to a lightsaber that was made during the KOTOR era? After all, it's a far older design than the modern lightsaber, being centuries out of date, so by your logic it shouldn't be nearly as efficient and effective as a ligthsaber built during the Clone Wars era.
Also, checking the Wookieepedia article on protosabers, aside from the external power source there's really not much difference between them and a more modern lightsaber.