This might bring a slight difference of opinion, but I agree with Christopher Nolan when he says that bringing Superman to the big screen is much harder than Batman.
This is exactly what the director and executive producer of MAN OF STEEL said on the topic, “In my honest appraisal, taking on Superman and creating that world is far more difficult than creating the world of the Dark Knight. He (Snyder) has a lot of finishing to do on the movie, it has a very long post-production schedule because, unlike Batman, Superman flies.”
While Superman and Batman both have human lives, Superman’s roots are not tied to humanity. This part of the monologue that Bill gives in Tarantino’s KILL BILL 2 explains it perfectly:
“Superman didn’t become Superman. Superman was born Superman. When Superman wakes up in the morning, he’s Superman. His alter ego is Clark Kent. His outfit with the big red “S” – that’s the blanket he was wrapped in as a baby when the Kents found him. Those are his clothes. What Kent wears – the glasses, the business suit – that’s the costume. That’s the costume Superman wears to blend in with us. Clark Kent is how Superman views us. And what are the characteristics of Clark Kent? He’s weak… He’s unsure of himself… He’s a coward. Clark Kent is Superman’s critique on the whole human race.”
You also have to have the right writer to take on this view point. While there is a piece of Clark that understands the feelings and emotions of humanity, he will always be detached. This is a harder subject to write on since (or I hope) most of us genuinely feel the pains and pleasures of what it is to love and be happy, among a many other emotions. We do not have to get a second perspective on what these things feel like. To be uniquely human is to feel. As probably many of you will agree, this is a topic we could talk about for awhile when it comes to Batman’s universe versus that of Superman’s.
Nolan admits how strange it is to give control completely over to someone else and take the back seat, “I actually feel guilty talking about it because I’m sitting here having nothing to do to it. I try to be as supportive as I can, and I’m just amazed by what he is doing. It’s not something I would know how to do.”