I remember a Bungie employee being interviewed last year and he was asked about something regarding Theater. The Bungie employee (I forget who) replied that he wasn't going to talk about "that feature". "That feature" was acknowledged right then and there for me. I was surprised to not find it in the game. I imagined it as a door in the Tower that leads to an actual theater that you and your fireteam could sit down in and watch back your saved films. I also thought there would be similar doors leading to things like Forge mode. :/