Maki just feels like a self-insert shipper to me honestly, A.K.A. basically all of us here. Your maki, everyone is maki.
The whole "I'm gonna obsessively watch them" stage felt really creepy to me.
Both of these thoughts clicked something into place for me:
While I still dislike Maki's narrative role as external observer/instigator (that he's a shipper insert eluded me entirely, such was my disinterest in him) and think he could easily be replaced by any number of characters or literary devices, it is the method by which his role is given context that really bothers me.
Why does he have to have a big explanation for why he's rooting for Yuu and Nanami? Wouldn't it be simpler for him to, y'know, just have taken notice? I mean, that he sees them kissing is more than enough for him to say, "Hey, it's none of my business, but I think you like her back." Why the dog and pony show to justify his ability to notice that two girls kissing each other and not be freaked out by it? (There might be a social aspect to this I'm discounting, I know, but even so.) Why does he need to monologue about being a romance voyeur to be able to notice that, yes,
@Franconator, Sayaka does seem a bit more than freindship-jealous about Nanami's interest in Yuu? I mean, regular people notice stuff all the time. I don't need an elaborate backstory to tell that the girl whose entire mood changes every time ABC-san walks in the room might be nursing a bit of a crush.
He's not the end of the world, and I don't mean to spend a lot of time on him. It just stands out, I guess, in an otherwise grounded and nuanced show, that they'd have a guy whose motivations require such deliberate and specific exposition.