It's great to like sex, but by playing wild and loose with it you're shooting yourself in the foot. No one's going to want to give you any once you have herpes and genital warts.
It was a bit of a slog in single issues, but even then you could see the brilliance of conception, slow as it was.
Wonder Woman reads better on a monthly basis, and has created a stronger cast of characters and built a stronger world, but For Tomorrow was a pitch perfect analysis of the Superman mythos, the core of the character, and a reaffirmation of it.
Superhero comic books only become art to the extent that their banal, unrealistic fantasy and garish styles go too far and become interesting. Attempts to ground them in reality can only ruin them.
You look at something like All Star Superman, or Moore's Whatever Happened to the Man of Tomorrow, or his For the Man Who Has Everything, and they are exploring the underpinnings of the character on various levels; either by systematically stripping away the trappings - the supporting cast, the secret identity, the faithful side kicks, the base, the villains - until only the core character remains, or by putting him in situations specifically designed to reinforce or fundamental elements of the character or are allegorical or what have you. And they resonate for just that reason.
And the same is true for Batman and the Dark Knight Returns and Morrison's run on that title. And so forth and so on.