It's less conventional than it looks. You'll see it being called a romantic comedy, but I think that's a slightly misleading description. Love stories are generally "boy meets girl" (or "boy meets boy", "girl meets girl", etc.) They end with the couple getting together and the story will be about their romantic journey. This show, though, has absolutely no interest in any of that, unless you count a budding romance in the last couple of episodes for a supporting character, Naoya. (The series ends with this unresolved, but they're adorable together and I have no doubt that they'll link up. Mind you, Naoya hasn't yet realised that Kou's female.)
This show has two couples, Narumi-Hirotaka and Hanako-Tarou. Neither has any real romantic trajectory. Two of them are already together at the start and the other two get together (quite casually) at the end of ep.1. This isn't a romance in the normal sense, but instead a study of what happens next. You've done the "getting together" thing, but what now? How do you handle things if you're working in the same office as your partner? Is dating a colleague a bad idea? What's it like to be a couple? More specifically, what's it like to be a nerd/otaku couple with strong interests in video games, cosplay, anime or whatever? (Those won't be the same strong interests, mind you. What do you do if your girlfriend loves Boys' Love manga and keeps encouraging you to read it too? Do you resist or go along with it?)
Oh, and these aren't high school students. They're in their mid-twenties, with office jobs and overtime. This is a Noitamina show, you see, so it's more for grown-ups than most anime is. What's more, it's also warm, funny and always entertaining.
They're not in the deepest pit of otakudom, mind you. They're capable of getting boyfriends and girlfriends, which puts them at the high-functioning end of the spectrum. (Hirotaka's borderline, though.) Hanako and Taro even used to be good at sports. All this has drawn criticism from reviewers who call its cast unrealistically functional and normal for "real" otaku, but I've seen other reviewers identify with it hugely and say it's just like them. Furthermore, Narumi, Hanako and Hirotaka are based on friends of the original manga author, while Tarou's based on his father. No comment. Anyway, this isn't a show about social lepers, stereotypes or caricatures. It's about a fairly normal bunch of grown-ups who happen to be super-enthusiastic about nerdy things and will often act like idiots, as do we all sometimes.
NARUMI is small, enthusiastic and a bit of a klutz. She has the loudest reactions in the show and lots of great comedy faces. She used to hide her otaku enthusiasms from her "Not One Of Us" boyfriends, but this never ended well.
HIROTAKA doesn't bother hiding anything... or indeed with visible emotions, or with too much interaction with other human beings. His brother Naoya bursts into tears on learning that Hirotaka's found a girlfriend at last. He's capable of being a bit insecure about this and wondering if Narumi's just putting up with him for convenience. (He also smokes. Personally I'd have ditched him just for that.) He's only interested in video games, but he's happy to go along with Narumi's enthusiasms, e.g. reading her Boys' Love manga if she pushes it on him.
HANAKO is confident, strong and a cosplayer. Curiously, she has an impressive figure but doesn't use it, instead preferring to cosplay as male characters. She and Narumi enjoy intense Boys' Love discussions and like seeing their boyfriends in suggestively gay situations together.
TAROU is the least nerdy of the four and it's quite easy for Hanako to embarrass him. He's also angry-looking and has a temper, so he and Hanako fight a lot. I hope their relationship lasts, but there's room to wonder about that.
It feels truthful, in its cute, entertaining way. Our heroes hang out and completely forget to do Couple Stuff in a way that makes them feel like real people, while the show avoids turning their lives into drama. They can be offhand, dumb or insensitive in a relatable way. They have different levels of how closeted they are. The show's unusually insightful and matter-of-fact about the girls' sex drives and urges. Everyone's firm friends in their otaku-ness, with the rapport that comes from understanding and regular leg-pulling. They respect each other's hobbies, as does the show. Occasionally they go to Nerd Faction War. (Would the correct Boys' Love combination be Hirotaka/Tarou or Tarou/Hirotaka? Narumi and Hanako take this question VERY seriously.)
It's great. I'm slightly nervous about the upcoming live-action film, because I'm worried that the producers might be thinking it needs to become a conventional love story. That's not what Wotakoi's about. I'll still be first in line to see it, though.