I just joined and this thread must be revived in the name and honor of the great Joruus C'baoth!
First off, his madness did not impair his powers. It made his judgement less than great, but when he was fighting, he was plenty tough.
-He can subjugate the minds of hundreds.
-He can use battle meditation to coordinate and strengthen attacks.
-He took down a ship with some rocks, using his power.
-He has the power to induce fatigue upon those around him, if he wishes.
-He uses Force Lightning.
-Almost no mind is closed to him, and he can use the Force effectively in battles to avoid attacks.
If he went insane, it could lead to: a) A powerful stream of relentless attacks no Jedi or anyone could defend against, or b) totally screw him.
It's a roll of the dice, but C'baoth could certainly defeat numerous Jedi or Sith. So what if he doesn't have a lightsaber? He can use his surroundings effectively and I'd like to see Mace or Maul slice at flying debris at them, while trying to fend off his Lightning.