Data
Always ask clients for data before scoping out alternatives, let alone making any judgment calls (and rendering legal advice based thereon) about which one is most consistent with, or least risky under, applicable law and practice. That's the way I was taught (in Chicago English). And certainly no basing of legal advice on anecdotes (or message board word-volleys).
For background, the variables appear to be safety of the nation's ATC system overall, volume of air traffic (with data sub-sets for sched carriers, GA, corporate, other operators like broadcast/traffic, and military), and technological sophistication of the ATC system infrastructure. If these factors are going to be said to be pertinent to evaluation of RT usages and practices -- and particularly if the question is whether the US should undertake to entrain an ICAO process relative to typical and customary ATCO usages and practices -- let us see the data. Don't know if it exists, or if it does, where. But this is just (if you will) pre-flight.
The harder data question is what specific usages and practices are trouble-makers, so to speak. If it is typical to verbalize altitudes and frequencies by means of digital expression (American 446, climb to three zero thousand maintain Mach 1.5, vs climb to thirty thousand...), isn't the question whether one or the other is better? Or are both safe and efficacious? Or is one better in certain environments or under certain conditions? Give me the data; leave your false patriot act on the ramp, whether foreign or domestic.
Next question (and it bears only a shadow of relation to NextGen): what if major US ATC installations all were switched to the equivalent of a CVN flight deck in high sortie rate conditions, or a front-line F-15 and F-16 air base in "high and hot" conditions (with or without high sortie rate)? Better ATC usages and practices? Yes, of course not everyone would understand - that observation here misses the point. This mil standard, as I have at least tried to describe and/or articulate it, is quite standard in actual practice, is it not? And this thread was opened by a plaintive cry for standardization, or was it, standardisation, affirmative?