The Hannah ending was way too ambiguous. Maybe that was intentional for Season 8, but we see her almost die in a hospital, then she escapes, and the next time we see her, she's dropping at plant off at Dexter's apartment. That's it. Deb never pushed Dexter on why he gave Hannah up, either. Was a bit out of character given the rest of the season.
Obviously, Deb wasn't going to shoot Dexter, but I was really surprised she shot LaGuerta. I figured she would have turned around and walked out and just let Dexter do what he had to. But wow, now she's actually involved. And now they have to explain why her gun was used to kill LaGuerta. If they find her. Plus, Deb's fingerprints and crap are going to be all over her.
My guess for next season is that the "killer" of the season will be a hunt for LaGuerta's killer. Maybe they ditched the body (wasn't revealed) and will try to make it seem like she bounced after the embarrassment of trying to frame Dexter.
I'm worried they'll kill or put him in jail (or Deb). It's kind of odd to say, given that he's a murderer and all, but I want him to have a happy ending.