From an article posted on the starwars.com forum, it was stated that the way you answer the questions will have a BIG impact on the way the story plays out, inferring that the story will differ quite a bit depending on how the FOUR endings worked out (DS male, DS female, LS male, LS female).
That's why I think Revan's going to have a major role. Having said that, I'm not saying that Revan will be a playable character, or will be the endboss. I'm just saying that it's a fairly good guess that his role will have a major impact on the storyline somehow.
And because of the above article about how you answered the question will make the game play differently, it makes me think even moreso that Revan will play a large role because it covers all angles. You played Revan as a female? Good. If you tell the game that, when you meet Revan she'll be female. Played Revan as a DS male? Same thing, you meet him, he's an evil looking man.
Obviously I could be completely wrong, but IMO, it's almost a given that Revan will have a large role in the game. What that role is, well, that's another story.