I think there should be areas larger than most depots or compounds, more elaborate and tricky. Then inside the area and slightly around it, there should be a lot more zombies than usual.
An amount where by yourself might get dicey or too risky, but with a group and teamwork might be manageable. Not saying this is a way to get people to work together, you could approach
it any way you wish, but as more and or better loot being the prize, people might do what they need to do. I’m not talking about a severe amount of zombies where regardless of numbers it
could become a suicide run, but a larger than usual amount. The area could be litered with corners, doors, holes, and a bunch of other things that could make zombies come out of no where or your escape
could be anywhere. Make it that so some ways take you outside the property, some that keeps you somewhat doing circles, or even and in a scary/adrenaline fashion, a dead end!
Basically a way of taking a survival game and putting in that adrenaline pumping action scenario you might find yourself in while in the search for useful items, rather than feeling secure about
taking down one zombies and or player at a time and just feeling safe knowing you can just as easily avoid the world if you wanted to.