I agree about 13 being very cynical against Kutner's world-view of being too trusting. That was really interesting to see the contrast between the two of them.
There's been such a lack of Kutner this season (i'm guessing that's because Kal Penn was so involved with the Obama campaign) so i was so happy to get to see more of him in this episode. I really liked his interaction with the patient and the way he warmed up to her when he found out he could identify with her on some level. And yes! I was so sorry for him when he found out she was lying! And then after that there was no more interaction between him and the POTW which i found really sad.
I liked the ending when he watched the patient reunite with his family. I think it would have felt really bittersweet for him.

Yeah, I got really angry with that POTW! Kutner is such a nice and trusting character so I found myself so pissed off that the POTW was screwing with him (although I certainly understand why she did it). It is clearly a very sensitive area for Kutner and it was actually really cool to see more of Kutner even if it was a crap situation.

I didn't really connect Kal Penn's Obama campaigning with his lack of screentime... Olivia Wilde was also campaigning for Obama, although she wasn't as involved as Kal, so I don't know how much of an impact that would have had.