I would like a game that combines Tarkov, Dayz, Fortnite, and Minecraft, along these lines, now, hear me out, I will try to be as detailed as possible.
So let's look at the idea behind this new game.
The basic idea of the game would be the ability to head underground and mine basic materials to make certain items, combine this with the ability to knock down trees, dig up the earth, and replace the earth/stone where you want to place it.
This could then be centered on solo player servers to "survive" but also team "servers" for people to work together to survive, of course, would need varying difficulties that either ramp up with the number of players to tone down, with fewer players online, so this would a "live" ability to make the game playable.
The Zombies I think would have to be taken from games like Dayz and movies like World War Z where sound itself can alert zombies to your presence and cause different reactions in the zombies depending on the zombie's "level" - Such as World War Z zombies were stupid fast and no wall was high enough without decent defense and water would be a natural barrier and the ability to create these kinds of obstacles to help the team or solo players survive.
The ability to create weapons must come in the form of items gathered, so my idea would be no "dropped" weapons or "loot" caches. Everything must be farmed and tool benches need to be used to create weapons/goods/barriers/tools etc.
This would force, for lack of a better term, players who work in teams to farm wider and wider areas, obviously the drop rates would need to be increased/decreased depending on the number of players involved and online, as I said before, the server would need to recognize how many players were online and adapt accordingly.
In terms of PvP servers, these would be purely about clearing the map of Zombies and enemy players, but things like treaties and clans could be built on the maps themselves, unlike other games, I would prefer personally that there were around 5-10 pre-designed maps that players are randomly assigned to when seeking PvP Maps. I think it would be funny as hell to build a base and to have enemies tunnel underneath you and come up in your base if you don't take the proper precautions. But, this being said, if a "group" or "clan" is not online, the base should not be attackable or lootable. I've never liked that idea.
Now with "transport", vehicles such as Jeeps or Helicopters, should be found, half destroyed that need materials to get them operational, HOWEVER, this being said, these materials must NOT be easy to obtain or "farmable" in certain locations on the map, the spawn has to be random and only there for a certain period before it moves to another location and spawns there.
This is a game that can be fought in caves, underground, and in sky-high structures, the player's imagination is what makes the game run, alongside the zombie "apocalypse". Players can be fighting in caves and get overrun by a "herd" of zombies or choose to fight together and survive, separate and live to fight another day or betray each other, players can be working together to secure the map, when the last zombie is "killed", essentially completing the map and then "rebuilding" society or, the adventure ends.
There can be a back story as to what happened that caused the world to come to this state but when I say "maps" I mean "massive" maps, where players need to plan expeditions, food, and supplies before going elsewhere, like in Minecraft, you need food to survive long journeys, weapons that decay when used, etc.
Anyway, this is my idea for a decent Zombie survival game.
Feel free to poke holes in it :P