New Brevoort Formspring

I once heard somebody say that a retcon should only be done for 2 reasons: 1) To fix something that was broken or needs updating for modern times 2) To create new story ideas. However, the retcon in New Avengers Illuminati that the Beyonder is a mutant Inhuman fixed nothing, it made things more confusing, and didn't create any new stories since no writer has used the Beyonder since. What was Bendis thinking when he came up with this and what were you thinking when you allowed it?