From a little bit different perspective, I used to teach martial arts classes to women, men and children. One thing that was missing was training on what the escalation to an attack usually involves. Many trainers teach that there is an escalation of threats leading up to a physical attack (for example: aggressive behavior, followed by aggressive language, then testing out the victim by trying to intimidate them into giving what the attacker wants, followed by physical violence, at which point the supposed victim would react and fight back), and that an assertive acton by the intended victim can deter the attack. My training and experience says 'not so', that often the escalation part of attacks occurs well outside of the range of detection and control of the victim.
Consider the Taliban in Afghanistan training to attack the World Trade Center, Japanese in Manchuria training to attack Pearl Harbor, street punks in a basement training to attack a woman in a parking lot. Often the attacks are rapid and violent, stunning the victims into inaction. Women and men alike are not used to sudden attacks and do not generally train for them. A man walking from a building as a woman walks towards the building, they pass, and suddenly the man grabs the woman and body-slams her against a car, hits her once or twice, then does whatever his intent was to begin with. A man walking on the street, a cleancut teen walking beside him suddenly strikes him on the throat and the backs of the legs, then kicks him in the head, then proceeds with the intent of the attack. No warning, brutal, ultra-violent. These are the attacks it is hard to prepare and train for, you have to train your mind to respond in a martial manner. I feel it will have to be the same with firearms training. Do not learn to deter the attack, learn to keep your head and retaliate when you have been surprised.
When I worked in a retail gun shop, we often had people come in and buy a gun who said they had no intention of actually shooting someone, but just wanted it 'just in case'. Many of these were women and older gentlemen. Many men would come in and buy a gun, a holster, a couple of boxes of ammo, and had the intention of at least becoming familiar with the operation and handling of the firearm in case they needed to use it. I will not address the mindset of the purchasers (i.e. decision to kill if necessary), I do not know what that was as it was not within the scope of my job to interview purchasers as to their intent and resolution in case of need. I just sold guns and ammo and hunting licenses, not warrior training.
So, long roundabout way to answer the question, I would say that the first thing anyone looking for training will need to address is the gun owners' willingness and resolution to use lethal force if needed. And, BTW, I feel this is one area most concealed carry classes do not address in depth.