Yes, Darth Revan is still canonical. KotOR Revan is not.
He is mentioned here: http://starwars.com/explore/the-clone-wars/ep317/#!/media/commentary
And then referenced to in the Son's official Encyclopedia entry: "The Son was not a Sith -- his powers existed beyond the domain of the Sith Lords. But his natural affinity to the dark side granted him visions through the Force, wherein he saw images of Sith Lords past and future."
UPDATE: HOLY SHIT, THEY MADE A ENTRY FOR DARTH BANE: http://starwars.com/explore/encyclopedia/characters/darth-bane/
"But his natural affinity to the dark side granted him visions through the Force, wherein he saw images of Sith Lords past and future."
then later: "George was looking for two ancient Sith Lords who would bring some meaning who would be kind of a like an uber influence guiding the Son. And this was Darth Bane and Darth Revan."