It's been awhile since I've heard the story told, but essentially Nakamura was pushed very strongly out of the gate. Youngest IWGP champion ever. And he didn't get over, so they swapped to one of the other Three New Musketeers (which was Tana - Shibata may have already left NJPW by then.) As for the why, well the Nakamura we know didn't really come into existence around 2010. I've watched some of those early matches, and...they're perfectly fine. By the time he turned into the charismatic guy, Tana was the ace, and Okada must have been a Young Lion by then, and possibly could have already been annotated as the future aceWhy was Nakamaura a Fail as the Main Guy in NJPW?