In the late 90's/early 2000's, Shooto's MW division was exciting. They had 3 Japanese stars, including Mach, Nakao, and Kato, and a host of rotating foreigners, including Trigg, Cook, and Cooper. But, like the UFC LHW division, it can't stay this good for long without new blood.
Mach is gone from Shooto, and his career has spiralled downward. Nakao is still a good fighter, but it looks like he could never be a top fighter again, and he may not fight in Shooto anymore either. Kato stopped fighting for a while, and has done poorly in his return. And foreign talent are rarely "Shooto fighters" (exceptions include Pequeno, Shaolin, Moura, Louro, Denes, and to a lesser extent Cooper, Hansen, and Shields), so, of course, Shooto relies on Japanese fighters to be their stars.
Some young blood began to show up...
Seichi Ikemoto: This guy had all the makings of being a star. Charismatic look, exciting style, and a ton of natural talent. But he has never improved in his entire career. It's like he never tries to improve. There is no reason why he shouldn't be a title contender, instead of becoming a gatekeeper in DEEP.
Yasuyuki Tokuoka: This is another guy who looked like a potential star. Very good wrestler, looks like a total bad ass, exciting style. Has some nasty GnP and high impact throws. After going 4-0, he gave a lackluster performance against Hironaka, then went to draws with Iwase (didn't see this fight) and Ikemoto (almost getting submitted in this fight), before jumping to Pancrase and losing a fight there. WTF happened to him?
Kuniyoshi Hironaka: Won the 2002 rookie tournament, defeated Nick Diaz, and then got injured training for a fight with Nakao. Makes his return to MMA in Lithuania a year and a half later, wins a decision, then gets injured AGAIN in a BJJ match. Guy has great skills, but just can't stay healthy.
Hirofumi Hara: This is a bit of a stretch, but he obliterated Hironaka and gave a great performance (in a losing effort) to Tokuoka. He looked like he could be a good fighter, but he's been unimpressive ever since.
The only guy with potential who has fulfilled it is Kikuchi. But he can't carry the division on his own, can he?
Now there are two more guys at middleweight who could become contenders. K-Taro Nakamura and Shinya Aoki. I think both of them need to realize their potential for the middleweight division to stay interesting.