I don't know if this would help or hurt but a piece of advice I heard a long time ago from a LARPer was "A secret kept is a secret wasted." In this case, I think that would mean keeping a secret from us the players for a dramatic reveal later(when later may never come) is a misuse of an opportunity. The characters can keep secrets from each other though, and that in itself can be dramatic.
Maybe that doesn't make any sense. But food for thought.