The vast bulk of my flying experience has been within the US but I did have the privelege to fly in Japan for a few years. That experience taught me the value of standardized comm and I do cringe occasionally hearing some of the things said over radios in the US. I have also been guilty of this but I do try to stay "standard." What distresses me the most is when (pretty rarely) there is some foreign carrier who is clearly having trouble understanding but the controller just yells a little and then hands them off. Of course, this doesn't happen very often and overall I think ATC does an excellent job. By comparison, the Japanese ATC folks were VERY cautious and had extremely stringent requirements for traffic separation. They were so cautious that it was frequently infuriating. Of course, I do recall one or two incidents in Japan involving traffic separation.
My point is that ANY system (particularly a complex one) involving humans will fail at some point. Another poster mentioned that they should be designed to fail safe. I think that's a very good point and much more relevant than "who's ATC is the best." Clearly the system at KBOS was not designed that way. How could it be done better? I don't know given the constraints of geography at that location. Perhaps if we did a risk vs benefit analysis, we'd find that is the best way to do it. Maybe not. I don't know what the answer is. I do find it interesting, though, that it only took a few posts before somebody said "It's because the USA (atc) sucks."