Deb vs Harry as the voice in Dexter's head
I wasn't a big fan of Deb often demeaning Dexter, when Harry was always himself trying to help Dexter live up to the code. I imagine they did it because this is how Dexter imagine's Deb's feelings towards him once she found out he was a serial killer, but I think I would have liked it more if she had done better filling Harry's role. Deb as a detective finding clues and stuff was my favorite aspect of her character.
As for the role itself, do you think they considered Harry again or was it always going to be Deb? Who knows if Harry's actor would have even been interested at this point in life.