Yeah, the whole point to Kato was that he was an idealistic foil to Kurono, who was very accepting of the nature of the game and was willing to fight like Nishi if it meant his own survival. Kato's death was the best thing to ever happen to Kurono as far as his development went, but Kato just doesn't work on his own at all. I don't care how many ridiculously hedonistic strawmen you put him with or how much you make the old characters act like complete dicks for no reason to get that spark back.
Wait. Actually, I DO care! THE OLD MAN WOULD NOT FUCKING TURN HIS BACK ON INNOCENT PEOPLE, YOU LIMP-DICKED ASSHOLE! REIKA WOULD NOT JUST GO SHOPPING DURING AN ALIEN INVASION! WHAT THE FUCK!?