These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Black Dagger Brotherhood
Badass Decay: The Lessening Society in general, as of the last two or three books. As the focus has shifted to Xocr and the Band of Bastards as the new threat to the Brotherhood, they've gone from being a well-organized, professional force of supernatural killers to a loose band of psychopaths led by someone only ever referred to as "Little Shit". Oh, they're still a threat, of course, but not nearly what they were at the beginning of the series.
Although, it is stated that the war ebbs and flows like that, and has done throughout history. However, with Butch being reborn as the Dhestroyer and Xcor wiping out every Lesser in England and perhaps beyond, the Omega is certainly on the run by this point.
Crowning Moment of Sadness: Wellsie, her unborn son, and her cousin, Sarelle, are slaughtered by the lesser Mr. O in Lover Awakened.
Jane being murdered in Lover Unleashed and Vishous's desperate flight to save her was this Up to Eleven for some readers.
When it seemed like Xhex was going to die as Lash's prisoner after the Brotherhood had found where she was being held but had no idea she was still there thanks to a barrier which trapped her in a Pocket Dimension as if she was a ghost.
Pretty much par for the course of the BDB series. Each book will contain at least one monumental Tear Jerker.
Why Don't You Just Shoot Him?: Seriously, why do the Lessers even bother trying to throw down with blades or clubs or hand-to-hand with the Brotherhood? Centuries-old warriors that have mastered most forms of combat, and the pale boys go in for fisticuffs. So why not invest in some cheap Glocks and just shoot them?
That is indirectly explained in the books. It's mainly because they don't want to draw attention to themselves and shoot-outs in alleys and abandoned buildings are not a good way of keeping a low profile. If the Lessers can do it without drawing attention from cops or other humans then they'll do it, but keeping the war secret is more important than the advantage using guns all the time would give them.