I thought Superman Returns was an EPIC FAIL. It should've been called "Superman Lifts." Kate Bosworth (eat a goddamn burger, girl!) is the worst Lois Lane ever. Also, since the movie is supposed to come after Superman 2, how did Lois have any memory of her previous dealings with Superman? Even better, as Kevin Smith pointed out, after she figured out that Supes fathered her kid, why wasn't she all like "When did you rape me, Superman?"
EPIC FAIL on so many levels.
But Superman fails in general. He's an alien who looks exactly like a human--he even has red blood. He can fly, use heat and freeze beams, has super strength, can survive in the vacuum of space, apparently doesn't need to breath, has X-ray vision, and regenerates from the power of the sun. He's a goddamn plant.
His weakness is Kryptonite, which every villain in the series has warehouses full of. Luthor stabbed Superman in the chest with a Kryptonite crystal in Returns, but SUPERMAN DIDN'T DIE.
I just don't think Superman is relevant anymore. By the same token, they're gonna have a hard time making anybody give a crap about Wonder Woman too.*
*Brief aside: Megan Fox is, I guess, in the running for the role. This would be awful. I can't picture a worse Diana Prince. Aside from being brunette, Fox is the wrong body type to be Wonder Woman. The character is chesty, hippy, and strong. Megan Fox is a beanpole with a push-up bra and no upper body strength to speak of. She's also WAY too young. My vote would be Michelle Ryan (from the recent "Bionic Woman" show) who exemplifies all of Woman Woman's physical features and is also British.