I Think it would be extremely useful if we could choose to lock or unlock doors and chests!!
This option would enable us to leave chests at the new player spawn to help!
It would enable special challanges and events. Mazes and labrynths for our communities.
Bridges and arches can be left open to public if needed. I just feel the mechanic would be cool and usefull 
And minions!!
We should be able to set them to a mode. Not just guard or follow or scout.
Attack all. Remain passive. Only attack when prompted. Scout landclaim perimeters. Snipe. Hunt.
Theres so much potential. All that would alow much more strategic pvp.
And even admin hosted challanges with npcs would have more options!!!
Thoughts :)?