I think a lot can be learned by standardizing RT as some genuine posters have opined, the bashers that join in seem to have little to add however. As worldwide air traffic picks up, there's going to be pressure to place more aircraft into the same airspace and airports that exist. Eventually RT will come into the sights of regulators who are charged with making this happen and change will be upon us. The exactness of the RT standards does not support any large increases in volume, heck even RT what is complained about here has minimal impact, but it does support some additional volume.
The ICAO standard likely works well at medium intensity airports, but at airports pushing 700,000 to almost a million ops a year it's a limiting factor.
The Chicago TRACON (arr/dept) facility was evacuated yesterday due to false fire alarms. It severely effected the airport and when ops restarted the traffic volume was beyond anything I've ever seen there or elsewhere. One local controller (tower) was working three runways masterfully. Two departure runways and one arrival runway that all cross. He never stopped talking other than to catch his breath and accept readbacks. His instructions were clear and concise but likely not exactly ICAO standard. there wasn't anyone needing clarification on frequency, foreign pilots were mixed in and seemed to have no issues either. Other runways were also in use with a different controller as well.
These traffic levels are coming to an airport near you in the coming years. How the controllers will cope is the question.
Now a certain few posters will poo poo over what I've posted here, you'll be able to figure out who they are soon. However ask yourself the question I'm posing about increased traffic volumes and how that will be accomplished. My belief is it will be a number of factors, including changing the ICAO standard of RT.