The hurdles would be compelling government interest and strict scrutiny. As far as suppressors it can be shown that they are used all over the world by sportsmen and target shooters without issue.
I think these magazine limits and anti "assault weapon" things could get challenged. That would be under Miller. When the Miller decision came down the standard soldier issue was a '03 Springfield and a 1911. now it is a rifle with a changeable 30 round magazine.
As far as full autos, the NFA will not get changed on that at the federal level. It would be possible that states that ban them under state laws get challenged, but I don't think so. I don't think anyone is going to finance such a move.
