i have a small idea, reputation with factions (excluding zombies, their jerks) basicly, all factions would have a reputation with eachother, and most importantly, you. there would be things like bias (people in good faith with you value your actions more as good than bad, while the opposite is true for other factions. this could also mean faction wars, small shootouts between factions that you can fight in, or ignore alltogeather (but adrenaline might cause a small party to head to the nearest outpost or whatever, which may or may not be yours) participating in these would allow you to wipe out faction A (earning points with faction B), wipeout faction B (earning you points with faction A), or wipe out both, losing points for both factions, but earning double rewards from that battle. there might even be possibility for the ability to give simple commands to a certain faction's troops, given you have enough affinity with them.
i would also like to see guns that shoot saws that richoche and hit everything, severing limbs and stuff, but also damaging everyone, including you and your faction. you could also implement combat hatchets, which are good for both melee and throwing.
Thanks for the feedback. It is really nice to know your idea about factions. We've been thinking in something quite like similar with the factions, indeed. Reputation among them is a very powerfull skill we wanna explore. BTW, we are going to share your idea in our Discord Server, so please feel free to come in and participate in the discussion.
PS.: Do you like these concepts, so?