Nisemonogatari was a great addition to an already phenomenal series, but with too much unnecessary fluff. Recently I was inspired to try and figure out exactly what it is about the season that felt weak to me, so I guess I'm writing a review.
The arcs themselves were relatively interesting. Karen’s arc was lacking any real supernatural oddities, but that was okay because it expanded deeply on the universe, including the introduction of Kaiki, and fleshing out of Koyomi’s sisters and the previously stoic and silent Shinobu. There was actually a lot of content there, but I think seven episodes was a little much.
Tsukihi’s arc is a little more refined in its length than Karen Bee, but somehow manages to feel even more lacking in content. We find out a huge detail about Tsukihi, but when all is said and done, it’s really of no consequence. A couple new characters are introduced, but one is never seen or heard from again, and the other doesn’t really add much to this arc one way or another.
The first episode of Tsukihi Phoenix contains no real plot development, instead focusing almost entirely on what could be described as an erotic toothbrushing scene. And you know what? I loved that episode. But it was just another blip on the radar showing a trend I noticed throughout the season. There was just too much fan service.
I think blending fan service in with all of the other elements is one of the things that makes the Monogatari series shine as an anime. A little fan service is great, in the right time and place, but Nisemonogatari just seems to take it too far. A loli panty-flashing Koyomi, Koyomi bathing with a loli, sister-on-sister yuri, a girl molesting Koyomi, a middle school girl trying to seduce a clueless Koyomi... These are just a few things on the list, and I’m pretty confident that no other season has had quite this density of lewd material. I don't know if this was Nisio Isin getting a little overzealous, or if Shaft was taking too many liberties, but it's definitely there.
The characters introduced were mostly okay. Kaiki is perhaps my favorite character, with his charismatic lack of regard for morals which he backs up with clever wordplay. Karen has a deceptively deep personality profile, and is a loveable addition to the lineup of female characters. Tsukihi is a little shallow as a character. It feels like her only traits are her yandere tendencies and devout following of her sister. I don’t love Shinobu the same way a lot of the fandom does, but she is certainly an interesting character, and an adequate replacement for Meme.
Monogatari is my favorite anime series, but that doesn’t mean I can’t criticize it. Nisemonogatari had better philosophical dialog, character development, and art design you could expect to find in any other medium, but it still has its faults. I don't really like to give "scores," but let's put it this way: Assuming I’m only allowed to give Bakemonogatari and Monogatari Series Second Season a 10 at the most, Nisemonogatari would probably get a 9. It's a great show, but the shoes it had to fill were just one size too big.