Superman is also not supposed to have gotten younger after Superman II (when a portion of this movie takes place).

I think Cage could have pulled it off, the same way Christian Bale did with Bruce Wayne/Batman.

I think the biggest question I have is whether or not they'll deal with the absolutely moronic idea that people do not see Clark Kent as Superman, just because he's wearing a pair of glasses. I know my girlfriend doesn' scream bloody terror thinking someone else is getting into bed with her at night when I take my glasses off.