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.
Fandom Rivalry: With their prominent growth into the Idol industry, the mononofus often engage in rivalries with various bigger Idol fandoms, most notably with AKB48's. While it's all about Cool Versus Awesome, numerous pop divas with guaranteed hit songs battle overly energetic girls with more experimental songs, and when the two held concerts in the same venue almost simultaneously, the whole 48 vs 5 thing did not go unforgotten (even in the media). Sales-wise, though, Momoclo is still behind.
Some fans also got mad about the resurfacing of the Korean Girl Group Crayon Pop that predates all of their concepts and gimmicks.
Harsher in Hindsight: When you remember that the end of Shirome has Akarin be possessed by the titular spirit in exchange for their wish to perform in Kohaku, the sudden resignation of Akarin one year later becomes creepier.
It's Popular, Now It Sucks: Some fans have begun to feel this way, worrying that the group will eventually jump the shark. Even Hyadain himself implies this in his controversial tweet (which he later deleted after a couple of minutes).
Les Yay: Shiorin with everyone else. She often steals kisses from the others, onscreen. Akarin also jokingly pointed out that she has the tendency becoming les.
They Changed It, Now It Sucks: They went mainstream? They abandoned their school uniform and kimono mix? Akari is leaving the group? Shiorin is getting a haircut? Hyadain isn't composing the newest single? 5th Dimension concept isn't color-coded? NooooOOOOOOOO!
They Just Didn't Care: The whole Reni-chan's eating disorder issue in 2010 because her weight didn't meet ideal idol weight, her evolution is pretty horrific◊, but it seems even in the 2013 she doesn't recover well.
They Really Can Act: Considering how often they make weird faces, do strange routines and randomly yell on TV, their TV Drama series, Momo Dra gives off this impression.