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.
"There is something going on in time and space, and beyond time and space, which, whether we like it or not, spells duty." -Winston Churchill
"For of all sad words of tongue or pen, The saddest are these: 'It might have been!'" -John Whittier
"Apathy is death." -Kreia