I guess, I just don't think most of that is necessary. I mean, most elements in the FR are easily ported to other worlds with very few changes.
Take Murder in Baldur's Gateminor spoilers):
[sblock]It's plot hinges on a large city with tensions between the rich and poor, and a dead murder god who had children before he died.[/sblock]
Those elements could easily be found in most worlds. Even if they weren't, it could be adapted to have a different cause for the issues.
You are probably correct about the fluff but my comments also cover classes, monsters, items, etc.