Finally, with definitions and explanations came mining previous stories to show how it all "really" worked.  Yeah, I used quotes there (reference to another thread) but I think you can understand why.  They only "really" worked because that particular author of that particular title had a bugaboo about something they thought needed an explanation when, in reality, I never gave it a second thought.  Again, sucking all the fun out of what had previously been a rather entertaining story.  Why did I need to know that The Daily Planet was X number of blocks away from Clark's apartment or that Wayne Manor was exactly X distance from Gotham?  I didn't and still don't.  Couldn't care less. 

I've gone on at length about characters changing to become all but unrecognizable to me as the main reason why I left most mainstream superhero comics, but the origins of OHOTMU and WHO'S WHO definitely played a part for me as well. 

So handled properly -- as they are in a lot of SF literature -- the reader is never told the rules, but it's clear by what's going on that the writer is following them. This has a consequence of forcing the writer to write within the constraints forced upon him by those rules.

A simplified example might be: "How come we never see stories about Spider-Man flying under his own power?" Obviously, because Spider-Man can't fly under his own power. Even if the writer has a wonderful idea for a "flying Spider-Man" story, he can't do it. At least, he can't do it if he doesn't want to damage Spider-Man's (and his own) credibility.

So setting parameters is important. Even having fairly complex rules is okay as long as the reader isn't directly exposed to that complexity. Of course, writers will try to mine that ruleset for story ideas. Lesser experienced writers will seize on the first thing that tickles their imagination. Better writers will be choosier, and only use ideas that reinforce the core of the character. I would imagine it would be up to editorial to act as gatekeeper in that regard.

I don't need to know how far away the Planet is from Kent's apartment, mainly because such a fact would pretty much never come up in a story in any relevant way. But I might want to have a grasp on how his x-ray vision works, since it's used fairly often. If I were writing Superman, I sure as hell would have worked out exactly how his x-ray vision works -- consulting a physicist if I had to. I don't think I would ever offer up that explanation in any Superman story, but I would always make sure his use of that power fit with the model I had worked out.