Alan Moore tells what his process behind revamping Supreme was:

In George Khoury’s excellent book The Extraordinary Works Of Alan Moore Alan Moore tells what his process behind revamping Supreme was:

Well, when I was originally given Supreme, it’s so obvious that it is a Superman knock-off that has been based upon a kind of half-baked understanding of the comics of the mid-1980’s. It’s somebody who thought “Right, gritty realistic superheroes, that’s the thing to do. How do you do that? Well you take someone like Superman and make them a psychopath.”And so, he’d done that, and it wasn’t very interesting, the character wasn’t very interesting, none of the writers who worked on it seemed to be able to do anything with it because, actually, the idea of Superman as a psychopath is not a very interesting idea, and it’s one that other people had probably done better in other places years before. So when he [Rob Liefeld] initially suggested that I might want to write the character, I suddenly thought, “Well, how could I rescue this lame, appalling Superman knock-off?” And I thought, well, perhaps if I were to make it like a really, really good Superman knock-off, if I were to actually try -, because at the time, I remember thinking that the regular Superman book actually was at least as much of a lame Superman knock-off as Supreme was. [laughs]

This wasn’t the character that I’d grown up with, or that I was familiar with. It seemed like most of the more enduring parts of the Superman mythology had all been carted away, or changed into something more synthetic and less appealing. So I’d decided that I’d rather liked the old Superman, that I’d rather enjoyed that rich mythology and continuity, all those kind of stupid but enduring elements, you know? Krypto the Super-Dog, all of the old fashioned stuff that had so much more charm than the modern incarnation of the character.

And so, having come up with what I thought was the core intriguing and whimsical idea of The Supremacy, the idea that there was a some place where whenever a comic got revised, all of the stuff that had been revised out of the book ends up in some sort of limbo dimension. And that every conceivable misguided version of the character exists there somewhere, out of continuity. And once I’d come up with that fairly simple idea, I realized just how rich and funny I could make my treatment of it. The idea of a planet with hundreds of Supremes, every conceivable variation and where of course I could parody the various ills of the comic industry and where I could play with wonderful ideas, you know? Which was always the thing that Superman represented to me as a child. It didn’t represent to me power or security or anything like that; it represented wonderful ideas, ideas that to me at that age were certainly magical. Where, to me, they provided a key to the world of my own imagination. As so what I wanted to do with Supreme was to try and give some of that sense of wonder, some of that pure imaginative jolt that I’d experienced when I was first reading comics. I wanted to try and give that to the contemporary readership so they could get an idea of what it had felt like. The kind of buzz that those wonderfully inventive old stories and comics and provided.