As you may have heard, WP 3.7 changed search and enabled relevancy as opposed to strict date desc ordering of search results.
I have come up with a switch to toggle this on the main site, but it seems like the already existing order_by parameter (as per http://wordpress.org/plugins/json-api/other_notes/) to json-api doesn't work (anymore?).
For example, I have tried a search term and order_by=ID as well as date, and both returned the same exact results, ordered seemingly by relevancy, probably affected by the core code changes.
Here's the example output for both
Specifically, pay close attention to id #25038.