So much wrong here... You're first statement lacks any evidence other than your opinion.
Secondly, Vitate is not "all powerful".
Thirdly, nothing has been shown to confirm that Baras is more powerful than the Emperor's voice. All Baras did is trick the Voice he I did not overpower him.
Finally, Scourge is not more powerful than the entire Dark Concil combined. That's a bunch of nonsense. All the codex claims is that even the most powerful council members avoid offending Scourge. Which doesn't even mean he is more powerful than them individually let lone collectively.
Anyway, Malgus is certainly one of he most powerful Sith of the time taking the combined prowess of the four greatest heroes or either side to take him down.