So there were slave traders in Fallout 3 or NV (can't remember which one), and you could actually become a slaver. Just snap a collar on someone and tell them to start running. For me that was actually pretty fun (yes I'm a horrible person). I was wondering if we could have something similar in a DLC in a new area, kind of like The Pitt DLC from Fallout 3.
Let's say you get word about people being kidnapped and taken away to , and you decide to investigate (mission given from random NPC wearing a bomb collar running up to you [or you go to the area via radio broadcast like in FA3]). Then you go to the new area, where you have to complete missions to try to get inside the main slaver citadel. It should be big, kind of like the Pitt. After finishing the final mission, you can either choose to become a slaver and dominate the area with the slavers as the leader, or destroy the slavers and make the citadel a refugee area. Either way it should become a massive settlement.
Just my ideas. Also bring back the circular saw weapon. It rocked.