When you want to put kibana 4 export.json under git (or any VC system), you'll see that the file changes even if you did not touch searches, vizs or dashboards. The script below uses jq to keep kibana 4 objects (and object keys) in a constant order. Thus, no diffs if you left your kibana untouched. And more git friendly!
Here is the gist : https://gist.github.com/jpparis-orange/e79dbfae1cba54799b1476fb4ddfed93
Would it be good to have Kibana itself exporting objects with a constant order?