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: Genshiken
Ensemble Darkhorse: Asada. Not even named in the original manga, you know her as the girl with the constant cat mouth.
And Madarame. There is a reason he has three quotes at top of the page and at least five character focus chapters.
Fan Preferred Couple: If the proportion of fanfics is anything to go by, Kasukabe and Madarame.
Kasukabe can be seen as Sasahara's The Lancer in the Genshiken Doujin Arc (the Haraguchi and the Sasayan vs Kugapii incidents). Being the Nerd Nanny, she plays the role of Team Mom in the later volumes, especially to Ogiue.
Ohno (at one point the Older and Wiser to a confused and tormented Ogiue) turns int a sort-of The Lancer for Ogiue in Nidaime, though shared with Sue.
Kuchiki ends up as a rare mix of Butt Monkey and Team Pet, and shows a Tagalong Kid role on the Comifes chapters (his mission being getting the desired doujins for everyone).
Of course, each president after the first one gets to be The Hero, and the group's dynamics change a bit as a consequence.
Misaimed Fandom: The entire point of Madarame is that he's the living embodiment of "talks a good game, can't follow through". Don't tell that to the shippers...
Relationship Writing Fumble: Kasukabe and Kousaka's relationship seems to be based entirely around them being physically attracted to each other. It's not clear if this is entirely intentional.
Obviously there's more to it, as they're both still together even after graduation. When Kousaka isn't wrapped up in his hobbies, he's a surprisingly caring guy.
Ron the Death Eater: Kousaka sometimes gets this treatment in fanfics that are Madarame X Kasukabe.
The Woobie: Almost every member of the Genshiken can be counted as a woobie; however, the standouts are Ogiue and Madarame.