as for blizzy, japan isent overrated because they dont have a lot of "Big Names". Such as Korea, China, Germany, Poland, ECT. So they arent really "rated" at all.
Most of us know whats going on in Europe BW wise, but not so much in china. There for we know that Europe has some good players. BUT since we dont know whats going on in china we cant really tell weather they are good or not. All we can go on are names such as PJ and WYW.