I think the Colbert Report, while it was in character, wasn't more of the real Stephen Colbert than I was led to believe. He's really not that different than he was on his other show, for better or worse.
His interviews are still, by far, his biggest weakness. They've always been so painful to watch. In fact, none of the late night guys do good interviews anymore. I'm not sure if that's their fault or the agents/managers/handlers of the celebrities and politicians who are interviewed. They're 90% scripted. That's why I like when Fallon does the games with people. You see a lot more of their personality when they're playing stupid games.