Actually, shooting to wound would be a defense against either a murder or attempted murder charge.
Shooting to wound is for the movies. The rush of adrenaline one gets when one is fearing an immediate attack is so great, and civilians are so untrained generally in shooting, that the risk is fairly high that the shot will not even hit the intended target - the aggressor.
And lest anyone think that is poppycock, read reports of shootings by police; these people are trained in shooting, go through numerous practices, and when the brown stuff hits the fan, report after report will detail the number of shots fired and the number of hits. At times there are numerous rounds fired and few hits.
Center of mass is the instruction most often given because it is the biggest target, try hitting a target that may be 6 inches wide (about the width of a thigh) at fifteen feet when it is moving erratically, and you are under pressure. The results should be a wake-up call.