...and a lot of other tooling assumes the order is relevant. Quite a lot of application logic in the real world, too. Which is why browsers preserve iteration order.

JSON is a serialization format. Its components inherently have a serial order. You can't change this any more than you can legislate the value of pi to be 3.

Agreed, and if you want to write tools that are conformant with both specs, you really don't have a choice. The RFC pretty much spells out this point: "JSON parsing libraries have been observed to differ as to whether or not they make the ordering of object members visible to calling software. Implementations whose behavior does not depend on member ordering will be interoperable in the sense that they will not be affected by these differences."

(This kind of text is why I prefer the ECMA document -- it's clearly written to be a normative standard, rather than as a field-report and Request for Comments.)

Here is our opportunity to publish an ANSI or ISO spec, and take the market by storm. :)

Personally, I will adopt the first version of JSON that lets me insert a flipping comment!