Finished the season.
The first episode was kind of bad, but it got redeemed by killing off Mary at the end. I truly wasn't expecting this, so kudos, I guess. It would have still been better to not have her be some super secret agent.
I overall enjoyed the finale, but the very end (the part with Mary narrating) was kind of a weak (and corny) ending. "You are Sherlock Holmes and John Watson" [as they run out of a building]. Eh. I really wanted a personal scene between Sherlock and Molly. The best scene of the episode was the one where he had to save her. Man. It was tense. Like, Denis-Villeneuve-Prisoners tense. That scene needed a companion one at the end of the episode. Not necessarily have Sherlock and Molly get together (though the romantic in me really wants this to happen), but at least some sweet scene.
Anyways, yeah, you guys were right that this was the weakest season. By far. Here's hoping the next one is better (and doesn't take three years to get made).