You forget one thing: If they were to release 3 pieces of gear for each article every DLC, you'd be getting DLC's every 10+ months because they'd have to design brand new pieces of gear with their own unique abilities otherwise people will bitch and complain that all the new Exotics have the exact same abilities as other Exotics, on top of that they would have to create more missions, strikes and raids to go with said DLC's. It's too time consuming on their part and that results in people losing interest, by the time the first one releases, half the community would have gotten tired of waiting and just left. You have to see it from their point of view: Earlier DLC = More money.