DC is undoubetly a powerful universe (At least compared to Marvel, maybe not Image since they have characters like Spawn and GOD.), and Superman is probably the most powerful hero, yet he has enemies like Lex Luthor, Toyman, and the Prankster. Now, Luthor is undoubetly cool and he can pose a threat to the big S because of how cunning and intelligent he is. But the other two? Really, even considering Luthor's cunning, there just three normal men. Morgsn Edge is a norman guy also isn't he? I don't know much about him. I know that Superman has some powerful and unstoppable villians like Doomsday and Metallo and Darkseid I guess. Brainiac is cool as well, even though I hear that they retconned him. But really, for such a powerful character, he has one of the weakest Rogues gallery in superhero comics.