I'd like to start off by saying Thank You to the devs of Necromunda. We're all totally excited for the release. I hope your all enjoying the discussions we're having, and I hope that your thinking about using some of the idea. @lilstrid if the devs aren't reading the forum posts, please could you pass on my thanks, and maybe some of the ideas suggested.
@DeTortor, I'm thinking of starting a post to thank the devs for all their hard work. I think it'd be nice to encourage them with praise. Cos mostly we're all just trying to suggest ideas for them. Maybe if we shower them with thanks, they might just think about our ideas. 😂
With regard to diplomacy, apart from negotiating for a return of a hostage, I'm not sure it's, either, a) lore friendly or b) game friendly. However, inter gang trades might be a good idea too put in. I could work well, at random points an offer of stash or equipment could be made by a rival gang. Plus you could also offer a trade to a rival. I also think that a similar thing could work for hostage negotiations, one gang could offer a set amount of stuff for the release. It's either paid, or they could try and rescue the hostage. This way there are two possible mission you can go on. 1) hostage rescue, 2) hostage defence. If you successfully defend then you can choose to kill, recruit (if gang types are the same) or sell to pit slavers.
You make a good point @DeTortor. However, In the original lore, the underhive is massive. I mean the size of multiple cities. It felt, in my opinion, that most gangs had large territories, which spread out through things like domes and settlements. So if the game is based on, say, a city sized area I could imagine only about 15-20 large gangs controlling the city.
Thinking logically, the under hive is a cramped space (lore wise). So the amount of persistent gangs would depend on the size of area that rogue factor are thinking of setting the game in. I would hazard a guess that between 15-20 persistent gangs vying for territory. These could represent established gangs, and then we could have random gangs to add scope, representing smaller gangs trying to gain a foothold.