I wasn't as thrown by Dexter agreeing to keep an open mind about Ellen, because we already know that he's become more open to killing people who don't fit the code, and it was clear that his mind was truly open, not leaning in either direction but letting himself be persuaded by the evidence (and yes, I do realize just how degraded my standards are that I'm willing to give Dexter a pass for even contemplating Ellen's murder). What chilled me was Dexter's response to Miguel's outburst after learning that killing Ellen was off the table. I think that, for the briefest moment, Miguel's life was actually in danger, and I'm shocked that he doesn't seem to have realized this.

What interested me about the Camilla story was that everyone around Dexter took it for granted that killing her was the right thing to do (even if they weren't willing to brave the law and their own discomfort to make it happen) whereas Dexter kept thinking about it as murder right until the end. It's not the first time the show has concentrated on the ways in which, by a very strict reading, Dexter is more moral than the normal people around him, but it is, I think, the most egregious instance of this.

I'm not worried about Anton turning out to be the skinner because, as you say, that's been done, but I am worried that he'll be dead by the end of the season. I like him with Deb, and a long-term relationship with someone who is good for her seems like the next logical step in her boyfriend progression. I'm worried, though, that the character we'll end up keeping into next season will be Quinn, not Anton.