Think that the only thing they have confirmed for first DLC after launch is terminators and their equals. They might add dreadnaughts in the first DLC, or they might add it in the 10th dlc. We will find out once they decide on them. But being able to spawn as one would be awesome!
I hope that if they bring Dreadnoughts into the game that it don't kill the game like what happened to SM. I believe that they should incorporate them in a after death situation. So that it is more like your soul goes into the dread, not like the transport and tanks at spawn base.
i'll leave these here EDIT: dang-it second one was supposed to start at the dreadnought scene 58s all