Can only agree, the US has horrible RT. Canada's is just as bad. A little while back a Canadian ATC controller instructed pilots to go around using RT slang. Something like "sixteen twenty eight go around". The ATC missed the prefix of their callsign and the pilots didn't understand it was for them. They ended up landing.
I've heard the RT of both the SFO tower controller after the crash there, and the Heathrow tower controller after the BA crash a few years ago. The SFO controller sounded like he was trying trying to rap a song.
English is my natural language, I fly in busy airspace, yet I just about managed to make out what the SFO controller was saying. Those poor, poor foreign pilots have no hope. Even a United Airlines pilot in his witness report said the SFO tower controller was very rushed and it all sounded confusing (something along those lines).
The US' poor RT standards have lead onto a lot of incidents, it's only a matter of time before a crash.
Yes the UK isn't ICAO standard, but most differences are clearly mentioned in the CAP413. UK is not perfect. The US is horrendous (especially for ICAO level 4 English holders).
One last thing. What ever happend to mayday calls in the US? It's all "emergency" now.