If you're going to have balanced combat, diplomacy isn't viable. Apocalypse develops from the point of the incident where it is most chaotic, social ties don't influence probability of survival immediately. Most of the population is going to die anyways and it is mostly chance as to whether any citizen survives. The beginning is the "New World," or colonization. Like in the colonization of the very initial colonization of the Americas, individuals had very similar overall chances of success as those of families and organization. Notably in history this period is the longest. During the apocalypse, this period is the shortest. People don't need to learn how to survive off the land, they need to worry about the logistics of equipment. While the basic requirements of the body in antiquity will remain constant, the skills required to satisfy them are dramatically reduced. Given the threat of zombies, robbers, and murderers (not mutually exclusive), defense is the most important resource. Without weaponry people can't survive. They can't raid towns for food, they can't protect themselves from marauding bandits, etc. Since weaponry is vastly available and impossible to independently fabricate (compared to the past), the world is immediately divided into the armed and the weaponless in a matter of days after the initial panic. Once this hierarchy is established, the colonization stage fades into the "frontier stage," where three groups exist. Two, the family and the criminal exist from the "old world." Among these preexisting groups the rate of the survival of each party member is dramatically reduced compared to the new group, the individual. These people can have been from anywhere in the old society. This is the world of DayZ, this is the character the game must serve to.