1: Make the world more destructable, stuff like a concrete wall should crush under a tank or an apc. Stuff like a fence should not damage an armored vehicles. Also make it so you can see damage on car, not just a smoke(Bulletholes and scratches)
2: Add more parts to vehicles: Engine,Rotor,glass(to repair glass with bulletholes) Tailrotor, lights(basically add ability to shoot out lights of vehicle and replace them) Add a toolkit to repair vehicles more efficently(Without it the HP repaired would be less) Make vehicle physX much more realistic, no more bumping on hills etc. Make rain hit windshields
3: Make houses have boarded up windows and also have glass. Make them have doors to open. Make loot spawn inside lootable containers instead of just dropping on the ground.
4: Make NVGs less OP and make lights more preferred. (Add effects to the nvg, limit FOV etc)
5: More interactable things around in the world(Stuff like ability to breach a boarder up door/windows etc)
6: Servers should have up to 100 PoPcap and maps size should not be forced in presets but rather user chosen.
7:Game should be alot more moddable, ability to change UI,Textures and core mechanics.
8:Much darker theme, since you are focusing on pve and survival nelson should make the game feel more apocalyptic wich stuff like ground fog, Storms (maybe even radstorms like in fallout). Also maybe some “HELP” or “GET AWAY” messages in blood like there was in 2.0.
9:Character model: Simple, just add a thumb so reloading will look so much better. (maybe 1st person only)
10:The atachment system showed in Devblox #5 looks very nice, a better UI and it is perfect.
11:Now theres one thing, damage model. I think the damage model should be more realistic. Pistols should be able to kill easily at close range, but quickly drop off at medium to long range, should also be able to move faster,aim faster and reload faster with a pistol. (This will makes pistols actually usefull to have) SMGs should works somewhat like the pistol. Lesser range, lighter and faster to reload etc. Assault rifles would be the middle ground etc. Sniper and marksman rifles would be clunky and slow to aim and use in close combat but excel in long range. And should always be a one shot to body and head.
12:Now to follow up with this is the armor. There should be much more armor than just military and civillian vest. He should add everything from Chest rigs with no armor to Heavy plate carriers. You would be able to inspect it and it would say what the armor was rated for. (.22 - 50cal) Same with helmets, should be different armor values. A motorcycle helmet should be able to stop a .22 but a 9mm would punch trough and kill the user easily. Helmets should be ignored if shot directly in the face(Unless it has some sort of balistic visor)
13:Now for basebuilding. It should have many more tiers, from stick to Reinforced Concrete. Bases should also be able to withstand much more and also take much more effort to build, making them more usefull in the longrun. Since loot is rarer I think having a much safer place to store it would be good. There should also be custom models instead of just: Floor,window,wall etc. Should be stuff like a helipad, freeform concrete wall etc. Also LMGs should be used as lmgs(Supressing) and not raiding tools.
14:Zombies. They should pose a much bigger threat. They should roam around and not be static. Runner zombies should look like a normal zombie so they would be disguised. Add zombies like bloaters and screamers that attracts zombies(Maybe to unrealistic). Megas should be much rarer and also much more powerful. Zombies should be able to go everywere on the map like in 2.0. They should also look less cartoonish but still keep the style. They should also only be able to destroy wooden doors and various misc buildables. (Unrealistic when they bring down entire wall)
I made this a long time ago for reddit, much of this I believe has allready been suggested.