Okay, so the whole idea was that as the story went along, the exact nature of Superman's erasure would be uncovered and reveal why places like Metropolis were erased with him: rather than just a simple time warp, Luthor had become aware of his fictional nature and (with help from Mxyzptlk) re-wrote the universe's 'story' so that it doesn't include Superman. Since Metropolis is Superman's city, if Superman was never part of the story, then there was no reason for it to exist-- same with Smallville: no point in Clark's hometown taking up narrative space if there's no Clark to grow up in it. But, because of Superman's impact on influencing the creation of all the other superheroes that still currently exist, the narrative structure of the universe demands he be there, hence his mere displacement rather than complete removal.
All that said, I don't think the concept is going over well, and doesn't fit with the way this RP world works. Since I haven't posted in IC yet, I'm going to just go ahead and rescind my application. I'll apply again when I've got something that fits the scenario better.