I agree that a standardized structured format would be awesome, but I'm not convinced that JSON is it. And there should _not_ be more than one.
One thing that I do like about JSON is that it is ubiquitous - and that makes up for a lot of its other faults. But I would like to see proposed use cases that JSON would not support beforehand, to clearly define where the limitations are, and what limitations the community is willing to accept.