more zombies , zombies everywhere.
More variety zombie skins and sound effect. , If you can modify models and size of zombie , would be great to have different model for zombies.
no need for new feature or new ability among zombies. the current one is good enough (screaming, running, fast running, fast dog-style running) But if you can make crawling zombie would be nice.
Keep them real.
Ignore the FPS problem. I heard some devs dont want more zombies because it will cause the lagging. But hell, this is year 2018. The ones who got old toaster PCs should change and upgrade them.
disable grass options , adjust the old dark type of light.
Decreasing loots rates. Super zombie drop nothing (maybe drop meds) So people will killed it for exp only , or maybe kill for secure the loot area. rare items only spawn in item boxes, lower tier loots spawn on common grounds
Imagine in small city (clear view or small villa for example) is pack of full of zombies (like a lot and lot and lot of them) and add 1 or 2 super zombies lurking around. You got guns but not enough ammo to kill them all. stealth is the key, making gun sounds make big impact on life and death. Malee-ing zombies house by house , roads by roads , kill them one by one to get loot inside the house and food, You have to keep watching and looking out for Super zombie to avoid them because it cause you a lot of gun fire, and you get nothing from it, so you probably want to avoid them, or run away from them. Also looking out for people, and large numbers of zombies make pvp more difficult, typical loadout won't be enough to kill all the zombies and super zombies, running and escaping will have to be applied.
It doesn't have to be PVE focus , but surviving and difficulty is a must. killing players and seeing other survival players are still a thing. but plan and strategy have to be applied. Like "oh there a geared guy right there fighting zombies on the car. but he is too far away. I have mini uzi on me, no siliencer. If I walk through him directly straight I won't survive that another group of zombies. I need to go round to the less zombies area , sneak , sneak , malee zombies that I have to, and ten approach him and kill the lack-of-seeing-surrounding-type-of-guy down." And also the moment like all i found in these few hours are pistols and krugers and loud shotguns, but then you found an item box and it is M4 AR gun with 30 stanag on it ,and you are like OMFG, I need to go safe it in the safe zone.
numbers of servers are adjusted according to the players and the size of the map. Each region has only 1- 2 servers. faster zombies spawn , faster loots spawns , people have to scatter around the map to safely farm , taking risk and fight to people for good loot area.
Large map like this we don't need. big empty Forrest and roads and rocks are not fun. We need middle-sized compact map full of POIs (point of interest)
Larger map is needed when population grows.
Basically , More and more and more headcount number of zombies , more zombies skins