I rewatched Dexter season 5 for the first time since 2010
What I liked:
Boyd Fowler was an intriguing character and the cat-and-mouse between him and Dexter was wonderfully played.
The opener was great and teased a dark, reckless path that I felt the season should have explored more.
Jennifer Carpenter really gave it her all with her material.
The ending of episode 2 with Dexter discovering the barrel girls was macabre, classic, with Dexter almost relishing the sight of death in that it proved his instincts were right.
Concept of Dexter saving and helping Lumen was good.
It would've been impossible for any Big Bad to successfully follow Trinity so I guess the focus on a group of villains was... understandable?
What I didn't like:
Santa Muerte storyline felt like a waste of time.
Execution of Dexter saving and helping Lumen fell flat; second half of the season reduced their dynamic to love-struck vigilantes. Here's Dexter with a girlfriend who also kills people. Fans hated this turn of events at the time (at least, the fans on the old IMDb message boards) - hard to blame them.
Liddy was a lot of build-up for a character and storyline that ultimately got brushed aside way too easily.
Jordan Chase and the Rape Gang lacked depth and weren't developed well; Chase ended up as a generic antagonist and it was impossible to buy him as a threat to Dexter.
Entire second half of the season lacked stakes and momentum due largely to Chase's ineffectiveness as a villain. But also the story played out way too leisurely - the penultimate episode of the season saw Dexter and Lumen rooting around Quinn's apartment and cracking jokes about a cat that farts and hiccups at the same time. Again, this was in the penultimate episode of the season!
Sonia = transparent and uninteresting way to keep Harrison occupied and stop Dexter's storyline from getting too bogged down in looking after a one-year-old (this is a minor complaint).
Deb's decision to walk away and not look behind the plastic curtain is still maddening. Where other antihero shows were going full steam ahead with their endgame, Showtime was set on preserving the status quo. Missed opportunity - there would've been something ironic about Dexter's efforts to help someone (Lumen) being what ultimately led to his downfall. Wasn't to be.