NJ washed their hands of TNA. Mainly after Jeff Hardy bombed in the Tokyo Dome. Kenny has no desire of wrestling in the US anymore. He was in WWE development in the mid-00's, asked for his released, made it over to DDT in Japan and hasn't looked back. His declared intention is to be as big a star in Japan as a Japanese wrestler, not just as a famous gaijin.

You gotta break this one down for me breh
So is [insert pretty much every legendary wrestler ever here]
I'm interested, how are you measuring star power? Just by names you recognize? Doesn't really make sense given you don't know much about the Japanese wrestling industry, right? On relative terms, with Tanahashi, Nakamura, Okada, Minoru Suzuki, Sakuraba, Shibata, Kojima, Tenzan, Makabe, Goto, Ibushi, Ishii, Nagata and Naito, in terms of star power, the NJ roster is ridiculously strong. NJ's problem is actualy kinda the opposite, in that they have so many names they're not really building to the future right now. But in a relative sense, TNA's "star power" can't hold a candle to NJPW's. They have about a half-dozen guys who could claim were the top dude in Japan in the last decade.
Davey was brought over for a few tours in 2010/2011, he and Romero won the jr tag titles. Being the top jr? Nah, Davey's singles runs revealed glaring holes in his game. The dude was never quite as good as everyone wanted him to be post Daniel Bryan signing to the WWE when Davey was hyped as the new "best in the world", and it's why everywhere has cooled off on him some. I think most people have finally realized Eddie is the better one in that tag team.