When Heller told us that we would be disappointed when we will know who RJ is, I think he wasn't talking about his identity, but he was talking about his true nature, which means a coward.

That could also explain why the actors were chocked when they knew who RJ was.

Nevertheless, that doesn't mean that the episode was good. I'm still disappointed about the fact that we didn't have any explanation of RJ's past, as Heller promised that he would explain as clearly as possible.