Did he? I always presumed he was a unique creation for the Donner films. I don't recall any comics including Zod at all before the movies. Shows how much I know!
Oh dear. Looks like this one is gonna be a stinker. And people said Singer's effort was poor...
As for Superman being too powerful...my feelings are that he has far, far more human weaknesses than Bruce Wayne or Batman. Donner really fleshed this out and made a truly human superhero, something that later comic books and movies could hang their hats on (see All Star Superman). I think the real problem for many is that he just isn't dark and scary like Bats. But that's the bit I love, and what makes him eternally more interesting. An alien who's more human than us.
Zod first appeared in DC comics in 1961, so he was a well established character. I think most versions of Superman, whether it be the continuing comics, cartoons or Smallville have there own version of Zod, so as long as a new film brings something new to the character I will welcome seeing him.