...exactly who it should be: Yu Darvish, of course.
I already said everything I had to say on the matter a few weeks ago. I still vaguely believe that if Naruse had won the final game of the PL playoffs instead of Darvish, there's a chance he'd have gotten the award instead. But after Darvish's playoff MVP award and his record-tying 13 strikeouts in Game 1 of the Series, there's no question in anyone's mind about whether he deserves it.
The articles don't seem to mention it, but Darvish is actually the first Sawamura award winner in the history of the Fighters/Flyers franchise.