Everyone in the U.S. should be required to serve in the military.
Absolutely we need more trianed killers with PTSD and other mental problems.
I have to disagree with you here. First, very few in a military that is not off on Bush type adventures would ever see combat. And if there were ever to arise another Third Reich type nation, we will need people trained in military matters.
Second, our military has been instrumental in aid to disaster victims world wide. Our heavy lift bases overseas should be permant features, with other natons helping with the upkeep. When Mexico suffered that catastrophic earthquake, the Russians used their huge transport aircraft to ferry supplies to that stricken nation, landing and taking off at McChord Air Force base.
This should be the primary duty of our and the other large nations militaries in the future, with only and occasional swat at some tinpot dictator that tries to extend his insanity outside of his border.