You're right;
Revan did fail to defeat vitiate; but that wasn't the lynch pin of my arguement :p
I believe, And, cononically, revan didn't NOT draw on the star forge, revan just was *that* much stronger than malak.
And the "there's is no light side or dark side of the force" Is a big debate through all of starwars, but I believe that by revan being both a sit lord, by later Jedi master (or equivielent), that would show his mastery of both.
And if you think about it, drawing on near-death Jedi to gain force or health doesn't particularly show any leadership or charisma qualities, especially when, as you stated, it's possible to beat Malak without the assistance of the Jedi.
But canonically, he probably didn't drain the health from the Jedi as that is, as you said, dark side, so he only probably would of drawn the "force power" out of the Jedi,
But I honestly don't think he drew out of the Jedi at all, as doing so would kill them...
(And that's why I said the Jedi exile beat 2 of the 3 Sith Lords by herself. Nihilus still would beat the shit out of anyone who wasn't also a wound in the force.)