It'll never be tackled, but I was thinking the other day about how CTE (Chronic Traumatic Encephalopathy) would absolutely plague the Super-Hero world. I can't think of a comic-book hero who wouldn't suffer from it's implications after a while. From repeated jumps & rolls off rooftops, to high falls, to cranium poundings, both the big u's would grind to a halt after maybe 10 or so years.
I could see an edgier, indie book tackling this issue one day.
Signed, Debbie Downer/Buzz Killington