There is a degree of proportionality that should be reviewed before posing any laws or restrictions on any citizen.
Generally GA crashes in highly urban areas are not really a problem requiring additional restrictions.
If you look at the number of hours flown versus accidents that involve fatalities, as a group, GA is a very safe group.
From what I understand in the latest reports from today's accident, there was a Flight Instructor in the co-pilot seat on this flight. By definition, there was a professional pilot on board. It will be interesting to see what the FAA determines as the reason for the crash.
So if someone wants to fill a small plane with explosives and crash into a building like this one (no need to "go big", just terrorize), you're going to be ok with it?