Instead of merely destroying objects in game made by players, allow for a salvage skill that has people deconstruct almost every item (they or allies created) While it may be more time consuming, depending on the structure, it would help preserve resources that are currently not renewable.
Also, another skill, Anarchy. Only achievable after learning Theft, and Murder - Allowing you to sabotage houses or objects, either setting on fire or damaging it. Of course, introducing something like this should certainly affect karma, but to balance it so people don't just randomly do it. There ought to be some counterbalance, patroling npc guards closer to the center of the map might help. Just an idea.