Imho, bunkers and similar heavy stuff is too much, but placing wire sounds interesting.
An idea:
Player would pick the wire "weapon", click Fire (LMB) to place the point A, and then move around to define the point B. Press Fire again to settle the wire. Wire would dynamically change it's length and angle between the point A and the player in realtime (by adding or removing short wire objects between player and the point A) until he settles it, unless player gets too far from the point A (spend all "ammo") when the A point would start to move towards you leaving length of wire constant. "Ammo" would be defined by how many wire objects you have (They could be 1-2m long) so therefore you could have 10-15m of wire. Only when the wire gets settled you lose "ammo".
You can place it in portions. For example place 7 meters on one place and 3 on another place.
The same kit should have an ability to "cut" wire. Cutting would delete a single wire object and raise player's ammo by 1. It would be represented by pincers "weapon" and done by "firing" it. Similar to wrench.
Engineers should also have pincers and the ability to cut wire but not carrying it. The "Wire kit" should be unique, and found in bases.
Don't take this seriously though, I'm not aware how much time would this require to implement or is it possible, but it's a quick suggestion.
