Speaking as a veteran ... don't even start with the PTSD bit. There has been a lot of talk among certain circles over the past year or three about automatically barring anyone diagnosed with or treated for PTSD from firearms ownership -- FOR LIFE. Considering that a comparatively huge percentage of veterans returning from the sandboxes these days either have PTSD or probably have symptoms and haven't been diagnosed, this would be a terrible thing.
There's nothing wrong with the rules as they currently stand. Harless is a loose cannon. As far as I'm concerned, he has already had his second chance -- the incident that cost him his job was not the first time he threatened a citizen. The real issue about Harless and PTSD is that people with active cases of PTSD probably shouldn't be police officers, because being a police officer in some areas is a high-stress occupation.