I decided to write this review because Bungou Stray Dogs's MAL page only has glowing reviews, and while I do think there were aspects of this manga that were likable, I didn't see any review reflecting what I thought were some notable aspects of this series, namely its mediocrity and subscription to overused shonen manga tropes. I was honestly surprised that this manga is categorized as a seinen manga because I think it resembles a shonen manga much more. That aside, I really only found BSD to be above average at best, and here's why.

Story (5): The story is the main bone I have to pick with this series. It's very battle-heavy, to the extent that I'll sometimes just skim the battles to get back to the plot. The only thing that keeps me slogging through the fight sequences is wanting to know more about certain characters' pasts. What happens besides the fighting is a lot of typical shonen manga plot points: teaming up with the baddies, nakama power, making the baddies see the light, nakama power, overly tragic past trauma, nakama power...and it'd be fine if these devices were at least executed in an original way, but the way BSD does it just makes me want to yawn because consistently the story lacks development and relies on tropes to progress. So if you enjoy the kind of plot found in Fairy Tail or similar manga, you'll eat this right up. Overall, the story runs on action and flashy, overpowered characters and it lacks dimension. There is no exploration of an overall theme or idea, which is what I think defines seinen masterpieces like Naoki Urasawa's Monster. The most recent chapters show potential for taking the series in better direction, but thus far the majority of the series is still lackluster.

Art (8): What initially attracted me to this manga was the art. I read that its art was among the most liked in Japan, and I thought the character designs looked nice. The art quality stays consistently strong throughout the series, something I appreciate. The artist avoids the "Same Face Syndrome" that plagues many other series, and there's even a page at the end of one chapter showing how each character has a different eye shape. The artist is clearly quite skilled, and I particularly enjoy the color palette used in the color splash pages. The style is more modern style, and vaguely reminiscent of Yana Toboso's (creator of Black Butler). I do think there is an over-reliance on screentones, and the artist has some trouble with making older people actually look old and not just like young people with facial hair. But in general, I think the art is quite good.

Character (6): The characters have an interesting premise in this story in that they are all named after renowned authors, and their attitudes and abilities are reflective of the works of the author they're named after. I found this to be quite interesting, and the mangaka pays quite a bit of attention to making the characters consistent with the characters of the authors' most famous pieces (see the characters F. Scott Fitzgerald, John Steinbeck, and Margaret Mitchell) and I think I was able to appreciate this more because I had read most of the books referenced for the English/American authors. The references of the Japanese authors were lost on me, but I trust that they are equally as nuanced.
Beyond this premise that doesn't have to do with the story at all, the characters are largely cut-and-dried, relying on eye-catching character designs to disguise their lack of true substance. I think the most interesting character is Dazai, though even he is rather flat as it is still unknown why he joined the detective agency and what motivates him in general, though this may be revealed later as the series is ongoing. The mangaka tries to make the characters quirky, but it ends up just coming off as contrived and forced. The series merely skims over character development, causing a lack of sufficient reason to feel attached to the characters.

Enjoyment (6): Despite the subpar plot and cookie-cutter characters, there was just enough for me to read this manga up to the most recent chapter, so it's a 6 for enjoyment. The quality of the art definitely helped. There's enough plot material to keep me reading, but it's rather superficial.

Overall (6): I think this manga is a fine time-passer that looks great on paper but fails to deliver much. It's like a mix of Black Cat and Owari no Seraph drawn in the style of Black Butler. It might be a good read for shonen manga junkies but I found that it lured me in under the guise of an original premise, but showed itself to be rather mediocre.