About Dexter
I loved this season. I also thought it wrapped up a little too nicely, but Lumen leaving kind of brought it back down to Earth.
Deb not finding out about Dexter made sense because she's a cop, and you could see how much she struggled letting them go; she shot at Lumen, and if she had seen them, how could she let them go?
While I didn't care much for the Batista/Laguerta story, it shows that the other characters aren't stagnant pieces of a story. They are integral to Dexter's life, and have lives of their own.
Laguerta protected Dexter from Quinn, which she might not have done except for the problems she was having with Batista, and her previous attraction to Dexter. Also, because Deb and Quinn got together, Quinn was willing to overlook the obvious fact that Dexter was involved in something sinister and killed Liddy. Their relationship is also what convinved Dexter to clear Quinn, rather than kill him, or turn him in. Quinn had no evidence so Dexter would have been in the clear.
All the pieces of the story came together, even Lumen leaving, which I didn't completely like, but it gives Dexter hope that one day, some sense of completion could rid him of his dark passenger.
That is what Dexter has always been about small problems and pieces coming together to roll into huge problems for Dexter and his killing of people, which in the end he solves by killing more people, in this case, Jordan Chase and his followers. This season also showed a lot more of what kind of person Deb is beyond a foul mouthed cop. She didn't even ask Dexter for help that much this season. Like Dexter, she's much different from her peers and has had problems finding love. This season, they both found great loves. Dexter lost his love, and saved Deb's; he's a killer, but a great brother, trying to be a good dad. He saw Rita as his connection to humanity, but in his lss, and throughout the season he got closer to and struggled to keep the rest of his family close, and happy. I thought it was the best season so far, maybe.