Roman arguably lost to Cuadras. Gallo couldn't KO a no namer and he injured his hand. Again. Naoya struggled with and couldn't KO Carmona... injured hand. Naoya KO'd Karoon, but looked bad in doing so... injured hand. We could have had a sick modern day trio version of Pacquiao/Barrera/Morales/Marquez, but one guy is ineffective at the higher weight and the other two have looked less than stellar due to niggling hand injuries.
Naoya didn't struggle with Carmona, he just couldn't KO him, his hand was hurt and he still beat him handily (no pun intended) and still almost stopped him in the last round.
I thought he looked okay against Carmona. He stood and traded a lot because there was an urgency to get Carmona out of there (because of the injured hand).