That's so funny you say that because I do the same thing with All-Star Superman as the quintessential American Superhero Comicbook, I may have to try...
I always read the diamond form and diamond skin as the same thing...solid diamond...internal and external. It's why she was completely shattered and...
That's a loooot of speculation. Cable, who has lots of experience with them from the future, seemed quite certain the EMP grenade would do the trick....