Giving each Sith their own unique power is an interesting train of thought.
I want to add more supernatural dark side powers other then Force lightning. Everyone always talks about “the power of the dark side”, and while I understand they’re referring to it’s raw power, I think giving the Sith more “superpowers” makes it more alluring.
However, the idea is that the powers extract a toll, both on the soul and body. Which is why in my version, all of the Sith, not just Maul and Vader, look like monsters. Sidious’ face is not due to lightning being reflected on him but the dark side, and Dooku’s true form looks like a vampire. It’s the classic mythic trope of physical corruption due to dark magic.