I'm about 7 or 8 hours in, and I've only been doing side quests so far. Or, well, you know.
So, credit where it's due. I've been playing that long, and the Big Bad hasn't been revealed yet. Or maybe there is no Big Bad. Or whatever. I don't want to know. I have my suspicions. Either way, it's gotta be some kind of Bioware record. I can't think of any other game they've made, with the possible exception of Jade Empire, where the main enemy wasn't more or less obvious from the start. I'm very happy about that.