Superman is the most difficult to cast out of all the Superheroes. He has the most distinct look, doesn't wear a mask, and an alter ego with an opposite persona. It's one of the few where I need to buy in as soon as I see them. After one minute, I need to buy in a hundred percent. It's been done before. It can be done again. There's someone out there.
I really love talking about superman for this very reason, he is difficult to nail down as there are three distinct traits that are very different in essence. Each interpretation has tackled it differently.
From my own experience, Reeve had 3 traits. Farm Clark the true self, Office Clark and Superman acts, extensions of the other.
Lois & Clark - office Clark real person, Superman an extension.
MOS - there wasn't really much to differentiate them - farm clark, superman very similar and office clark more.. hmmm, his look seems younger than his superman look and not as brooding.
For me, i feel that we should see Clark's true personality when in the planet and as Superman, not just when he is in smallville and by that i mean - when Clark is Superman, rescuing a kid or talking down a criminal with a gun - that's clark - you don't want to be acting in that situation. However, when in front of the public, say just after a big event and news reporters are there or talking to a mayor - the superman persona should be switched on and the audience should be aware that that is what it is. Same at the planet, when he is investigating, negotiating his day, that's clark, but like us all, with his 'work' head on. There are lighter moments and we see clark's softer, human side, just as when he reports on injustice - i feel 'lois and clark' cracked this really well.
I have felt that 'the office' was a good template for humour in the work place - now, ofcourse certain characters and acts are cartoonish, but the jim, ryan humour in particular are a good level. BJ Novak should def be involved for added help.
If he were 10 years younger, 10 inches taller, Paul Rudd would have been my left field choice.