Very much agreed and if anyone challenges you on Heller I'm calling them stupid right now.Your last paragraph points out an important factor that may have been overlooked...."training to engage and eliminate active shooter threats".
That's why I am in the middle somewhere on carry restriction limits.....between no restrictions (so called constitutional carry) and registration of weapons/bans/major limits. Hell, even Scalia said in Heller (paraphrasing....can go get exact quote if challenged)...the 2nd Amendment, like many other rights is not an absolute. The 2nd Amendment is not a right to carry any weapon, anywhere, for any purpose. There are reasonable regulations that do not amount to a ban that are available to the state to combat gun violence/death of it's citizens.
I'm a believer in conceal carry of handguns for self defense. But I also think people need to demonstrate firearm proficiency and safety through a real course rather than a 4 hour class that focuses purely on legal aspects, not that the legal stuff is unimportant. Unfortunately I know people who carry that have no business because they aren't capable of responsibly handling a gun. I think if you expect to exercise a right to carry a firearm in public, concealed or not, that you owe the general public some level of assurance that you aren't more likely to kill 10 of them while trying to shoot at a single bad guy.