One mans trash is another man's quality of life improvement... My expectations are low, mainly focused on using a compare tool to identify that there is a change and locating where that is so I can review it manually and decide how to sync up the two versions. In that sense a compare of sorted JSON text (including sorted arrays (lists) of objects (dicts) - which normal semantic diff tools don't do) is drastically better at identifying real changes then is comparing JSON files as they are natively exported by Ignition.
@nminchin I may need to review your compare script and elevate my expectations 
I'm guessing your script assigns more significance to the 'name' key in determining if a tag is added/removed and that any tag name change would likely be detected as a tag removal and a tag addition (suppose I should look before guessing).
@nminchin @pturmel, thanks for the dialog!
I'll try to find some time to educate myself with respect to java.util.TreeMap and @nminchin's external compare script.