Creating
With wireframe its now possible to create objects with predetermined form.
For example, to create a vehicle, plane, or artillery, if they ever appear, you first place their empty wireframe where you need it. Then you fill it with blocks and the object activates and replaces the blocks. Same concept will work for 'reinforced walls' or whatever else ideas.

Weapons
Now that SMG is good as a weapon, I think it needs to do reduced damage to blocks.

Antigriefing
Maybe its hard for the server, but admin should have options for:
Blocks placed by allies can't be damaged by x weapon
Blocks placed by you can't be damaged by x weapon or other players
Vote for X player not being able place blocks