Vu doesn't destroy Specializations. Only sim inhabited buildings. I get irritated when it hits my Epic buildings and the world stops till they're fixed again. LOL That's the extent of it though. I can usually fix it all right away, but sometimes I don't have an item and it could take an hour or two to make. I was afraid of what damage he would cause too until after I started using him. Now it's no big deal. I delayed until I hit level 32. Had I known as soon as I unlocked it I could have expanded specializations a lot faster than I have been. They're slowly coming along now, but a whole lot faster than they were with just shipyard keys.