There are two ways to look at almost every situation. With your heart, and with your head.
My heart wants Japanese fighters to have success in America. I used to live there, I trained alongside a lot of Japanese people, and I like them.
My head tells me they never will--the average ones, at least--until they submit to the rigmarole of weight cutting and putting some serious time into training in the States.
There is one more thing, though. Rarely does an American promotion poach a Japanese fighter at the top of his game.
Takanori Gomi was taken apart with clinical coldness by Kenny Florian at UFC Fight Night 21. But when was Takanori Gomi last--really--relevant? From the beginning of 2004 to the end of 2006, Gomi dispatched a who's who of top lightweights. Jens Pulver, Tatsuya Kawajiri, Hayato Sakurai and Mitsuhiro Ishida. Since then, his career has been hit and miss, and the Fireball Kid has lost some fights he probably should have won.
Don't get me wrong, I'm not calling Gomi washed up or finished or Campbells just yet. My point is, if the UFC had have brought Gomi in four years ago, the fight may have been a different story. And I'm not making excuses for him, either; Florian won the fight by being a much better fighter. It's just that Gomi can't really be touted as still being one of the best lightweights in the world when there are a number of years between his best performances and now.
Caol Uno, too, lost his fight at UFN to a guy who sounds like a Brazilian steak; another apparent nail in the coffin for Japanese fighters. But I don't believe it. Uno, much as I love him, was already having trouble with the new breed of fighters back when K1 was running the HERO*S shows. He has been fighting for 14 years (despite still looking like he should be wearing a blazer and eating from a tray at lunchtime). He was the Shooto Welterweight champion 11 years ago. A legend he may be, but the next big thing he ain't.
As Mike Fagan noted in his post, the combined record of the Japanese fighters who have gone to the USA is 5-9-1. Pretty poor. But who are they?
Nakamura, Gono and Chonan were nothing more than top-middle tier fighters in the first place. Akiyama had potential but threw away the support of the industry by screwing over Sakuraba. Misaki could be a force to be reckoned with but has not been consistent enough recently.
Aoki Shinya will be a different story, mark my words.
He is the first Japanese fighter who we can legitimately say is at the top of his game. His recent opponents have, for the most part, been high calibre fighters who have put him to the test. His submission game is leagues above that of any of the other Japanese fighters to venture onto American soil. His striking, while not perfect--and not deserving of the praise he himself heaps upon it--is coming along. It certainly does enough to enable him to put his real gameplan--ripping people's limbs off--into action. He doesn't have the deathwish that other Japanese fighters do, either. He won't seek out punches with his face, doesn't subscribe to the yamato damashii--death before dishonour--philosophy that many other Japanese fighters do (much to their detriment.)
I think Aoki will win in style against Gilbert Melendez, and then he'll cry a bit, and then all will be right with Japanese MMA, for one night at least.