Then for the love of all that is good and holy LOOK SOMEWHERE ELSE! Spellfire may very well be the worst book I have ever read.
In other news... I once re-instituted Myth Drannor to its former glory through the use of time travel. I got tired of explaining all the changes to new PCs and went back to the old way. This is essentially the problem with canned settings like FR, especially when WotC has plot advancement in mind for the world. Who knows when THEY will decide to reclaim Myth Drannor in some novel and leave your little homebrew campaign feeling very left out and very off base.