I just want to put my $0.02 out there and maybe some of these ideals will take hold.
Doors can only be put in doorways on player created foundations.
Foundations cannot be placed within 30m of static buildings.
Boxes can only be set on foundations
Sleeping bags decay over time/use
Radiation poisoning causes vomiting after 350 rads.
Window frames - It would be a cross shaped wooden or metal framework that you set inside created window fixtures; thus eliminating the need for doors to be placed inside windows.
Hammer - A new tool that would enable the user to modify any building superstructure, based on the players unique substructure.
Night time airdrop - I just think an airdrop at night would be interesting, and probably easier to get if you were in the right place at the right time.
Forge - This could be reworked into crafting of weapons like pistols and rifles, also for use in creating melee weapons such as swords and bear traps at a later date.
Bear trap - causes the player to bleed and takes 40% maximum health; disappears upon server restart.
Snare - causes the player to be snared for a period of time, unless they have a hatchet to cut them self free; also disappears upon server restart.
Health meter for structures/placed items - just a viewable meter for the fortitude of placed items that only the player who placed them can see, it would make it much easier to tell overall decay.