I loved seeing the old school Cylons in this.

I agree with you that humanizing Cain seems to be a mistake.  You know, when you meet them they seem normal but then we find out how screwed up they are beneath that, and it's shocking because they strayed so far from where Galactica was at the start and where they are now.  You just get the sense that the crew made compromise after compromise and slowly lost their humanity. 

There's one moment from the series where you find out they have Tricia Helfer chained up in a room and the crew just indiscriminately has their way with her, and in my head that was the end result of a long sequence of events: finding her, questioning her, slowly stripping away her humanity until there's nothing less, real Zero Dark Thirty type sh*t, then at the end she's just like an empty shell, one of her guards decides to do an unspeakable thing, and no one gives a d*mn.  That's really horrifying.  In Razor, the idea is just a throwaway line... and it seems to happen really quickly.

It's one of those stories that doesn't really need to be told, because what's in your head is far worse than what they could tell you in the span of a movie, and it's sort of satisfying not knowing.