This season has been fantastic. Normally, once Premium Channel TV shows (HBO, Showtime) start to become stale, they don't return. Sopranos, Six Feet Under, Deadwood, and other great shows start off incredibly strong. But after Season 2 of Sopranos, Six Feet Under, and Deadwood after Season 1, they completely fall to ruin. They either forget what made them a success or can't figure out how to hold on to it.
Once I finished watching Dexter Season 3, I thought, "This is it. Dexter is over." Season 3 went in random directions at times, and ignored the success of Seasons 1 and 2. Dexter didn't kill anyone for himself. He didn't learn anything (other than the overall lesson of the season). It had no personality, in my opinion.
Season 4 broke this stale curse. It wasn't some dull misdirected meaningless story. It's own self-contained story of the Trinity killer was interesting enough. He was the first truly horrific serial killer. Dexter saw him as a mentor, and a friend, but Trinity's demons could not be contained. The writers weaved him into the Dexter mythos and with it brought more than just a lesson learned.
Now with Rita murdered as a Trinity victim, and Deb confronting Dexter about Brian Moser, I think Dexter has run out of excuses. It annoys me how everyone just believes Dexter when he makes up these flimsy excuses, and no one thinks anything else of it. I guess this is what happens when you kill off Doukes, the only person to actually question Dexter about what he's doing.
Thank god Deb has started assuming this role and actually asked Dexter about his peculiar appearance at the raid on Arthur Mitchel's house. I hope her role in Season 5 eventually leads to realization.
With Dexter only renewed through Season 5, currently, I wonder if the writers will end Dexter. Business-wise it would be a stupid move. The Season 4 Finale is the most watched episode of any Showtime original series with 2.6 million viewers. But Story-wise, it would make Dexter incredibly tight. It would never reach the point of being stale.
When Deb actually verifies the demon inside of Dexter, where would the show go from there anyways?