HiBC, I agree wholeheartedly with your premise as things sit now, but we've already seen an attempted copycat.
Thank heavens he was caught, and no, no body armor involved that we know of yet.
The premise is if this becomes more common what would be the best defense?
I profoundly hope I'm wrong but the increased availability of body armor along with decreased cost would seem to make this problem increasingly likely to happen.
The 5.7 and 7.62x25 rounds don't seem to be up to the task for good armor but may offer some chance. Training to switch to head shots at a certain point may hold more promise, but that's not saying much.
For about $200 I can get a tokarev pistol, and enough ammo to become skilled with it won't break the bank. If I have to shoot at an opponent behind cover it's penetration might be the difference between which of us gets to use a pine box. My ability to cheaply practice with my carry weapon is likely to make even more difference.Under those circumstances it makes sense for me.
The hard thing to think of is this, since the country's founding the RKBA has at least given the average joe the ability to cause significant damage to those who would attack him. These body armor suits change that. Specialized rounds or extreme skill seem to be the only good answer, and most of us have access to neither of those.