You know, people usually aren't that naive or stupid when buying real estate. If you buy in this building, you'd have to assume that the lot would eventually be redeveloped. If your building was across from a lot that was zoned for a 3 story building and they built a 20 story building, I might have some sympathy....but this is Market Street in Center City, man?!
Look at it this way, Kev. You'll have the same view as the other two sides of your condo building....a view of the building across the street.