I believe Mark Rosewater referred to the Weatherlight Saga as a failure.
Having played during the Weatherlight Saga, I can tell you the story was a massive failure. Competitive players just didn't care what Gerard did. I cared about making my opponent's life total zero.
I didn't look at the Weatherlight Saga until I started on the idea to run a Magic the Gathering inspired game about a year ago. When I did, I found it to be an interesting (if generic) destroy the world plot. It meshed with my desire to run a save the world style game.
Magic and DnD are the two games that brought me into the hobby. I don't play magic anymore (that hobby is for young men with more time and fewer responsibilities). But having done my research into it, I think it would make a fine setting and a great addition to DnD. The setting won't be everyone's cup of tea, no setting is.