I don’t know if it’s possible with the current engine, but what do you think of buildable trenches?
They would, or course, have the requirement that the engine is able to allow us this temporary terraforming.
Trenches should be limited of course.
They should also be connectable (that they transform themselves if you place some of them next to each other automatically) .
Maybe the buildmenu needs an upgrade, too, that the trenches aren’t highlighted each time you walk through them.
They should be indestructible. Only options should be to remove them after placement.
It would be cool if they could also provide some buidspace if you combine some trenches (like a lowered basement for trapps, towers or whatelse).
One more nice addition could be placeable ammo-boxes. You don’t always have the time to run back to the plundra or crafting station if you run out of ammo. Small boxes that could be built next to the walls or inside the trenches for deploying ammo would be helpful and offer another option to store ammo.
Currently, besides the plundra, you can just store granatgevär rockets, 7.62 and .50 in some structures. And this just if you own all basebuilding dlc.
One more thing:
A mine layer support structure.
You could be able to select some places where to place mines. Now feed this support structure with mines and it will fill up the selected places with mines automatically every time you’re not in combat (like between waves).