I was always under the assumption that he went to find something LIKE sith, but not an Empire led by a maniacal emperor.
I suppose she couldn't know everything. The reason I asked was because she's right about a lot of things in the game, and I was unsure about this one.
My take on this from what Kreia said is that Revan became the Dark Lord as a sacrifice, not by choice. He did it so that the Force would be in balance again. Similar to what Anakin did in episode 3, although he did not know what he was doing and he was a horrible character so that doesn't count in my mind.
The last part of your post makes me sad :/ Obsidian have always been the superior writers, Bioware should have listened to them.