Despawn times, and buttons. These two things.
Buttons, how they could work:
Set down a button, have a setting to connect it to an object. You click this setting, then click the object. Boom, button affects this object. Then set whether you want the object to rotate or translate. Set how much, then you can push it to do the action, and push it again to undo the action. Simple to do. AND you could have a set amount of time the object will stay in this position before it resets, making something like generator defense. (Have a door to close for a minute to give you time to regroup before the zombies break through.) Maybe set one button for multiple objects to have larger effects.
Whether it could be easily implemented or not depends on the engine.
Buttons, what they could do:
You could set a huge object to move across a gap as a bridge, have a "floodgate" to keep zombies out, make a conveyor belt out of a bunch of objects, or build a base with a few buttons to make forge tuts easier.