It was obvious from the very beginning. It's just that because Revan is the player character of the first game, nobody likes to see him as the amoral Sith Lord he was, because that ruins the self-insert experience.
Besides, it doesn't contradict Kreia's claim that Revan did it to save the galaxy from the "true" Sith. Like any tyrant, Revan no doubt believed that he would be a stronger and more benevolent ruler whose reign would save many lives.
The only new thing from this video is that now we know Revan's face and his lightsaber color post-memory damage.
"Grant Allen [...] had written a book about the Evolution of the Idea of God. [...] it would be much more interesting if God wrote a book about the evolution of the idea of Grant Allen." ~ G. K. Chesterton, The Everlasting Man