These are some suggestions that would probably bring DayZ back from the dead. (not saying its dead but it slowly is, but dw I still play it)
1. Safezones- Safezone should be added to DAyz so that players can, chat with one another, trade, and maybe team in peace, without getting ambushed while eating peaches together lol. You can make the safezones as small camps. With npcs, Military, Survivors,etc
2. NPC- should be added. If you walk upto an NPC it will say some statements and chat to other NPCs, but some can give quests. IF I walk up to a NPC they can say stuff like, "Hello", "How are you doing" or "DONT TOUCH ME or EVEN LOOK AT ME!" and stuff, its kinda funny. Some NPC can be found out of safezones, maybe a hunting tower, in small huts or inside a fortified house.
3. Quests- IF Quest were added there would be a reason to go somewhere. Quest are given by NPCs. IF you interact with an NPC you some of them will offer a job, like they need something. eg If I go to a medical tent and interact with the doctor he/she can give a quest for me to go to a town and find some medical supplies for her, and if I complete it she would give a reward such as food, water or anything useful
4. AI BANDITS- these kinds of bandits roam around the map searching for supplies or other survivors. They travel in groups from 1-5. If you encounter one they will scream out calling the rest of the group, they will be shouting "DROP ALL YOUR STUFF" but if you do they will kill you. There weapons will depend on where abouts they are. If in an open feild(stick,fists,bat,etc), A city(handgun with 2shots left),Military Areas(Rifles and gear). just make it obvious to see weather its a player or not.
5. Boss Zombie- A boss zombie is a highly grown zombie(about 2x a players size) and can spawn at a medium sized area. This will be useful so that people can challenge themself to try kill it and have a fun time with friends. AFter killing it, you can search its body and can find maybe ammo,armor,mags,craft items,clothing,etc (no OP GUNS).
6. Some small suggestions- Glasses- in first person there can be a crack on the glasses depending on the quality Add face paint-to look more savage, camoflage,etc