That's quite a long post, so I won't respond point-by-point, but I'd say we're generally in greater agreement than either of us probably would've imagined at first.
I see your point about magazine capacity, and I honestly don't have a good answer. Personally, I wouldn't be bothered by eliminating magazines altogether. The problem there is that I wouldn't dare suggest such a thing to a gun enthusiast, given the amount of pushback there is simply over limiting high capacity magazines. Suggesting limiting them altogether? Man, get ready for a shit storm.
As for mental health initiatives, I'm all for that. But again, there are issues. Most obviously, there's the issue of paying for all this, and it's never been popular with a good portion of the country to have any sort of "socialized care," or viewing such mandatory evaluations as an invasion of privacy. I wish those weren't issues, because regular checkups for everyone would have a huge benefit.
I agree with getting rid of bullshit regulations (like barrel length, which you mentioned), and at the same time, I would like to see the agencies responsible not have their hands cuffed when it comes to enforcing the laws that most can agree on (hate to be "that guy," but Jon Stewart really nailed the issue last night as to how the ATF has been castrated).