I agree...but I think the whole season was a disappointment. I felt the writers got too "cute" with their "twists and turns" and took away the essence of Dexter's character, as well as Deb's. Deb's ability to "normalize" as quickly as she did was hokey, and I thought Dexter's obsession with Hannah was very uncharacteristic of him. 40+ years of being a certain individual, combined with training, pissed away as he found a "connection", which, he never had.
The ending was an example of the writers pussy-ing out. I thought about it for a few days to make sure there wasn't an angle I didn't see, but ultimately, I felt like the writers didn't want to finalize the series, or Dexter, in the way they should have.
The best part was Batista watching the video of Dexter "Defending himself". Thought Batista's expression was quite funny.
Overall....awesome series. Awesome characters. Awesome in every way. Except the last one....I felt ripped off by it.