You don't think a motivated individual could kill and injure about as many people, in about as much time, by just driving a box truck into the waiting line in front of a popular night club, or something? I get what you're saying, but I still believe that the problem is the motivation / mental state of these people, not the specific tools they choose to act out their horrible vision.
We don't have an epidemic of people driving box trucks into schools to kill children, and parents don't run their children over with box trucks when they mistake them for an intruder in their home. The fact that people can still do horrible things to each other doesn't mean that we shouldn't make it harder. Also, how do you propose fixing the mental state of these people? Are you lobbying for increased funding of mental health programs in your area? Calling your senators? Volunteering your time to help those with mental health issues? Or are you just saying this problem is unsolvable despite the fact that almost every other country on earth has solved it?
Is that a solution to a problem, or just a change in social mores? It solves the problem of people being dangerous with guns, by stopping them having guns. Same as with legs. Most crimes and dangerous actions are facilitated by the use of legs, so further harm reduction could be carried out by cutting everybody's legs off. And personally I'd support that, I never liked walking much anyway and it annoys me when people have busy lifestyles, but the plan won't get widespread support because it's against customary expectations. People enjoy, and expect to maintain, the use of their legs: they claim it's important.
