Gun Rights in the United States

I'm not an expert on Guns or Gun Rights, I have a vast array of other things that consume my attention. But I do have a few considered observations and questions.

Concessions:

1. US gun rights are derived largely from the 2nd Amendment to the US Constitution with the language:
   

   A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.

2. I stipulate that there is a Natural right to self-defense, but I hold that this must be carried out in the most ethical manner, as we hold in the balance the power to violate the Right to Life (which is certainly the greater Right) of others with this power
3. I stipulate that this self-defense applies to the people against tyranny of government (not imagined tyranny)
4. I stipulate that the militia referenced is of the Va. Declaration of Rights §13 (1776), in 7 Thorpe 3812, 3814 (referring to “a well-regulated militia, composed of the body of the people, trained to arms”)
5. I stipulate that this right extends to the 'whole people' (one way in which this Right has already evolved, as it used to be only 'men')
   

Observations:

1. The 2nd amendment is the only amendment that explicitly states a purpose behind the law
2. That this is the same Constitution which once held an amendment creating a disastrous prohibition on Alcohol production and consumption, which was so atrocious it had to be quickly redacted after having done irreparable harm to the security of the United States (funding massive criminal works that drove corruption and violence), harm we have never recovered from and harm that continues today in the illegal (unconstitutional) federal prohibitions on 'drugs' (an overbroad misnomer)
3. That this is the same Constitution which institutionalized slavery, which required massive bloodshed to eradicate
4. This this is the same Constitution that once forbade women from voting
5. Even in D.C. vs Heller, the Court stated "the adjective “well-regulated” implies nothing more than the imposition of proper discipline and training."
   
6. We require education and training commensurate with the task for the friseur and the doctor and the motor vehicle operator, but not for the "well-regulated" militia

Questions:

1. Given the Constitutional errors evident from our plain history, does it not seem that the Constitution is, just perhaps, not necessarily a perfect document for all times and places? And may, perhaps, from time to time need to be fitted to new knowledge of the world and new circumstances?
2. Given the repeated and increasingly intensifying tragic events of gun violence, does it not seem evident that perhaps just a bit MORE of that 'trained to arms' and 'proper discipline and training' might be warranted, in our current time and place?

Conclusions:

I'm currently opposed to a full out ban on guns in the United States, but nobody seems to be actually proposing that; except in the imaginations of people of questionable motive. It's not even clear to me that an 'assault weapon' (a complicated misnomer) BAN is the right approach (regulation yes, training yes, background checks yes).

Nor am I deluded, education and training alone will not solve all of our gun woes (certainly not in the short-term) - but the question is, will it help? It certainly seems wise to consider a path that increases the level of education and training required to gain access to such a powerful tool that, even in innocent hands, brings daily death and destruction to so many lives.

I think we can do better without sacrificing necessary freedoms.