I actually can understand why some “Sherlock” fans were less than thrilled with its fourth (and apparently last?) season.  (I’ve read that the final episode received the lowest ratings in the show’s history.)  Even if Season 4 wasn’t quite as strong as past seasons, however, I’d still give it a 9 out f 10.

The narrative style and the content of this three-episode arc changed drastically.  The detail and methodical pace of past seasons gave way to a faster, looser narrative that made the show feel more … mainstream, in a way.  These episodes felt more like the standard adventure tales that you’d expect from any television thriller, and far less a genuine homage to the literary source material.  At times it was a little sloppy, with bombs, disguises, false memories and other over-the-top plot devices that were sometimes pretty implausible.  The final episode even seemed directly inspired by a series of horror films not known for being critically acclaimed.

The writing and directing wasn’t as clean, either.  This was easily the most surreal of the show’s four seasons — especially if you count the standalone “special,” “The Abominable Bride,” which preceded the official initial episode.  There were some overly stylized flashbacks, spliced scenes, and other departures from a linear narrative.  (I can’t be more specific without spoilers.)

The tone of the humor changed, too.  Some of the droll, dialogue-driven British humor was replaced by the zanier, crowd-pleasing stuff that you would expect from a more mainstream television comedy.  (One lamentable scene involving the outcome of a car chase, for example, was entirely too silly.)

At the same time, this was the darkest season yet.  The goofier humor was juxtaposed with story elements that were hard-hitting, sad and occasionally frightening.  When one character delivers the line, “Maintain eye-contact,” it was chilling enough to stay with me hours after the show aired.  There was some scary stuff this season, on a couple of different levels — the second episode, in particular, superbly delivers creeping psychological horror, then tops if off with a chilling story resolution.

And here is where Season 4 shined.  At one point, I asked myself, “When did ‘Sherlock’ become a horror show?”  But it was shortly thereafter that I realized that I absolutely didn’t mind.

The season’s success boils down to three things.  The first is the darker story content, which I thought was a bold and surprising choice for what is probably the show’s last season.

The second is the quality of the writing.  I realize that sounds strange, given my above criticisms above, but it is still a superbly scripted show.

And, third, the performances from its principal actors were still uniformly excellent.  (And when they combine via some great dialogue, “Sherlock” still hits it out of the park.)  Martin Freeman, Benedict Cumberbatch, and Amanda Abbington were all at their peak — particularly since their characters have evolved now to what is probably their culmination.  This last  season was easily the most personal and character-focused, and sees these protagonists finally complete their individual arcs.  Sherlock is finally sufficiently humanized, Mary’s development finally reaches full fruition, and Watson has finally grown into his own man.  If I had quibbles about Holmes and Watson’s portrayals in past seasons, it was that Holmes was too much of a jerk , while Watson was merely a weak, even neutered foil for him.  Holmes was never such a heel in the stories I loved a boy — neither was he in the film adaptations.  And I found the far stronger Watson in “The Abominable Bride” to be truer to the stories as well — not to mention reminiscent of my favorite Holmes films, like 1976’s “The Seven Percent Solution” or 1979’s “Murder By Decree.”

The villains were damn good too.  “Sherlock” has always excelled at bringing believable, well scripted and creatively conceived bad guys, and this season was no exception.

All in all, this was still terrific television, despite its relative flaws.  I heartily recommend it to Holmes fans.