DandD said:
But wasn't the Forgotten Realms Campaign Setting always changed to fit the new edition rules? I mean, that's what the so-called Times of Troubles is all about, after all, isn't it?
Haven't you seen the lynchmobs that formed after that disaster?
The better solution was what they (mostly) did in 3e: they just "restated" things to fit the new rules. Let me give you an example.
In 2e, which didn't have sorcerers, the Simbul was probably a high-level wizard. In 3e, which had sorcerers, they then just said that the Simbul's A Sorcerer20/Wizard 10 (or something very much like that), and had always been. The rules/mechanics that described her changed, but she remained her old self. They didn't do a big RSE to explain why she suddenly casts spells based on how pretty she is.
I can totally see them doing that for 4e, too: So Drizzt now has a quick, "surgical strike" fighting style and does some manoeuvres. It's still Drizzt, the guy with two scimitars. Elminster is a 4e Wizard now, and fond of his staff. He's still his old self!
Eladrin are called Sun Elves in the 4e Realms. An Eladrin and an Elf procreating produce a full-bred Eladrin or Elf, not a mix (or maybe they do, if there's a half-eladrin, half-elf race in 4e).
The cosmology is just assumed to be like this, and having always been like this. They did that in 3e, too, and didn't need a RSE for that.
Nothing of this really requires slaughtering dozens of deities and millions of men.