I kind of wish the show would take some of these character developments it flirts with (a darker and more aggressive Dexter in this one) and actually run with them. Bringing back Brian in his head had loads of potential, but since they decided to simply put an end to it in this episode it just seems like a brief little gimmick to fill up the season. Also, interesting things are happening regarding Gellar. Either he's actually real and a large percent of the fanbase has been completely off the mark, or they're just trying to mask it a little more.
If he's real, they're making damn sure everyone thinks he's not! But if they want to believe that he is real, they need to drop some subtle hints that he is! So far we got nothing.
I loved this episode (even though it was another of those "filler" episodes to extend the season), and I agree about what you said Seth. I wish they would've run with that more, and I guess they could, with all the light/dark that this season has gone about I guess they could bring Brian back (being his dark side to Harry's light side), but it's highly unlikely they do.
At any rate, next week we should be back to DDK for the rest of the season. And who else thinks Travis' sister will end up being "the whore"? If they wanna show the audience that Gellar is real, I can't think of a better way.