An interesting tidbit from Margaret Weis on ENWorld:
Although we didn't know a lot of what was happening at the time, TSR was going bankrupt. Summer Flame was originally supposed to be three books involving the search for the magic that is lost at the end of Summer Flame. Management decided that SF would only be one book and that since Tracy and I were no longer with the company, DL would pass to an in-house team and it would be tied with the new RPG card game the company was developing to take advantage of the craze with Magic. And so, DL went a different direction.
What no one foresaw was that this would split the DL community, with some fans liking 5th Age a lot and others not so much. When WoTC took over, Peter wanted to see DL come back together again and he brought me and Tracy back on board to work with the 5th Age design team to bring the two together. Tracy came up with the idea that Takhisis had stolen the world--which I thought was absolutely brilliant. And we went from there.