Yes but remember the dreadnought was Originally planned to be in Vanilla, the writers have a really long scope into the future of Destiny, its not like they start writing one dlc after one is released, not to mention the first E3 destiny was at made it sound like you would be defending the city, in the city, so its not out of the realm of possibility, we've made enormous strides, killed Vex and Hive gods, killed every ranking Cabal on Mars, killed the Kells of Winter, Devils and Wolves, and not to mention What we do in stopping SIVA, so if the Vanguard or Speaker dies in Destiny 2, i wouldn't be surprised.