This sort of thing is done in the States all the time. The gov't sells distressed properties for a pittance which are located in areas they want to build up, and the properties always have a lot of rehab strings attached. I think it's a good idea, if the end result is investment is in a slum area and to rehab of buildings that would otherwise rot and be left to squatters and druggies.
The strings attached to the buildings are that the buyers must invest a certain amount of money, build to standards, and not resell in a certain amount of time (to discourage speculation).
The difficulty here is that so many buildings are 'public' but not strictly 'government' owned - hospitals for example, and schools, many of which are simply bulldozed, despite being solid buildings of some architectural merit, when new ones are built.