If He Wasn't Ray Palmer/The Atom.....
He'd be a PERFECT Superman again. I mean he's definitely not too old to do it as he's only 1-2 years younger than Stephen Amell who plays Arrow. It's a shame that the movie he was in as Superman sucked balls completely I don't blame him one bit. He was perfect in it. Even got Reeve's mannerisms down perfectly. The movie just was a joke altogether. I actually blame Bryan Singer for that.
Someone in another thread said "It takes more than imitating Christopher Reeve to be Superman" which is true, but let's face it, Reeve set the blueprint for the on-screen Superman/Clark Kent and it's almost eerie how well Routh did it in his movie. Normally I'd use that as a justification to keep him away from a role like this, but in this case, it's a rare "Why not?" He was just so good in his movie and to me he was the only saving grace in it for that alone. Cavill was way too weird playing Superman as a guy with no sense of humor and way too serious. It just doesn't fit, plus Cavill is way too buffed, man he looks like he overdid the spinach and thrusts for the role. Routh has that look that goes well with the Superman persona. He should've done Man Of Steel. He looks way better for the role.
Honestly, if he wasn't playing Ray Palmer/The Atom, i'd vehemently try to push for him to be Superman in the TV series of The Flash and/or Arrow because since there are so many crossovers between the two, especially with The Flash being a series now that's doing great, Superman will have to come into it somewhere. It's almost unavoidable. And I'd say Brandon Routh would be perfect to do it. Yes, he was that great. And even though comic book hero movies aren't exactly regarded for their casts' stars acting chops, he really proved himself to me in Superman Returns. He's great.