I just finished my reread of this - it's definitely my favorite manga of all time (and also by far the best poly rep I've ever seen in manga). I'm bumping this thread to bring it to more people's attention possibly, and also just because I wanted to leave a comment.
(I don't think it's the "best" manga I've read, that's definitely Bloom Into You, but it's good enough, and it's by far my favorite)
It's certainly unusual, and I would say highly successful, in its structure--there are lots of manga that are not unlike YagaKimi; it just does those things in a truly excellent way.
AnoKiss, though, tries something that I don't think I've ever seen in a limited-arc romance manga before--a central couple surrounded by a whole constellation of secondary relationships that take turns taking over the spotlight, so they aren't "sub-plots" but temporarily become main plots.
The whole thing is worth more than a single reading, for sure.
I think the way that Anokiss took all those separate relationships then thematically connected them back into the main relationship by having Shiramine talk to people about them to try and figure out her own is just... chef's kiss (though the fact that they didn't have Moe and Mizuki acknowledge they were more than friends is cowardice). I also would have liked to see like 1-2 more chapters of closure on Nagisa and Hikari (and an entire spinoff about Amane/Nina/Ryou, those 2-3 chapters are literally my favorite piece of any manga ever I'm so starved for cute polyamory - I still don't think it was rushed really, the things that needed to happen happened, concisely, but well done).
Also, I think Anokiss is more "normal" than Yagakimi, even though Yagakimi is a pretty standard story - the way emotions are explored through Yagakimi sets it apart from the norm more than the unusual nature of Anokiss's cornucopia of lesbians does. I think they're both interesting and wonderful separations from the standard, but I do think Yagakimi is more "different" from the standard recipe. It's ultimately a difference in presentation versus a difference in themes though. They're both so wonderful, I'd forgotten that Anokiss was like, actually good, as well as really really fun and enjoyable and wonderful. I had, in my head, reduced it to comfort food of a sort, not ultimately fulfilling or special or poignant just deeply satisfying and nice, but it is good, it really is deeper than I ever remember. It covers actual problems and weaknesses and emotions and just... god it's so good.
Sorry for suddenly ranting and losing all my coherence in this second paragraph I really love this manga and none of my friends read the same sorts of manga as me so I suddenly had the opening to express how I felt about it.