Pairing: Tachibana Makoto/Nanase Haruka
Canon Level: Best Friends
Makoto and Haru: Best Friends to Lovers. The friends to lovers trope is completely my jam. There are other tropes I love as well, but that one is definitely on my top five. Given how important each of them is to the other, I don't think it's a big jump for them to go from platonic to romantic love. I think the biggest impediment to that sort of relationship is what, if anything, will get one of them to risk upsetting the status quo of their friendship. Like, I can see Makoto as being self-aware enough to realize his feelings but also self-sacrificing enough to not be the one to say something first. I don't believe he'd feel the need to say anything so long as Haru seemed content. Their fight in season two could be seen as counterevidence that he would say something, but I don't know. If Makoto had gone to Tokyo while Haru had stayed in Iwatobi, then physically their relationship would change--e.g. it'd take more effort for them to see each other because they lived far away--but that wouldn't necessarily mean that the relationship itself and their feelings would change, just how that friendship is expressed. And while lot of times a change in expression can lead to the relationship itself changing, it's not inevitable.
Okay, after typing all that out, I think that a forced change of the status quo of the expression of their friendship could lead potentially lead to Makoto confessing (which is why post-canon is great because it delivers that forced change so prettily it practically has a bow on top), but I think it's a decision he'd take a long time to reach. And that it's not a decision he'd be likely to reach at all while still in Iwatobi.
As for Haru, it's not that I think he doesn't feel things deeply so much as he doesn't feel a need to label what his exact feelings are. It'd probably make perfect sense to him that any feelings he has for Makoto are different than those he has for Nagisa or Rei because the way he relates and connects to Makoto is different from the ways he relates to and connects to Nagisa or Rei. So there needs to be something that causes him to examine his feelings more deeply, and that's tricky.
So yeah. I love these two, I love the depth of their relationship and how well they know each other and how comfortable they are with each other.
Suggested reading:A Momentary Itch
by meifaceHome Port
by ShimegamiHow To Read Your Best Friend
by themorninglarkyou know where to find me