I always thought that apart from not using honorifics and occasionally mistranslating jokes that only make sense in japanese, they were very accurate with their work considering they are the legal way to buy and read manga in the west.
Well, I'm a translator in real life (not of manga though) and I can tell you translators are humans, they can be flawed and they can make mistakes.
Though, if put in a simple way, there's usually two types of translators: the ones who tries to be as loyal as possible to the source text even if it makes the target text seem unnatural and the ones who tries to make the target text as natural as possible even if it makes it disloyal to the source text.
Translators are often asked to be the latter. Since the publishing houses often decide the target audience doesn't care about the loyalty to the source text as much as the fluidity of the target text. And eerily enough, a lot of translators happily comply.
But I like many others see this often leads in increasingly disloyal, lazy and rushed translations.
There's a french term for this, they call it the "belles infidèles" in reference to women "who are beautiful but always cheat". Critics on promiscuous women aside, I think that's a fine way to put it.
Also Izumo's interactions with Shiemi and Suguro were a major focus when it came to showing Izumo's character development even more so than her interactions with Rin considering her relationship with Rin didnt change much from beginning to now while there was substantial changes in her relationship with both Shiemi and Suguro. And even in that Shiemi's attitude towards Izumo never changed, but in case of Suguro, both their attitudes towards each other gradually changed overtime (and even in Suguro's case, his interactions with her were given a lot of focus when showcasing his character development).
Again, what you're saying is irrelevant to romance. You don't calculate attraction by the amount of character development they make each other go through.
It also makes sense from character development point of view since these two started as hating each other and gradually developed into vitriolic best friends who deeply respect one another. If this is the end of the development between the two, then it is fine and honestly I would prefer that be the case but if the relationship between the two is going to develop further than it is very likely that their relationship might turn romantic (which I dont like but I do see it happening) since they already are best friends at this point of time and we are only little more than halfway through the series .
A slippery slope argument?
Though I wouldn't even call them friends let alone best friends. And anyway, if I did, that would be bad news for their chances at romance. I'm among the ones who thinks that "acquaintance" branch out to either "friend" or "lover", that it's not a straight line where you have to go through "friend" to go from "acquaintance" to "lover" and that you can't call someone a "friend" and a "lover" at the same time.
But, I know, eternal disagreement...
I was only bringing that up because Juzo and Mamushi's initial interactions were almost identical to Suguro and Izumo's initial interaction right up to one getting physically violent with the other. Not to mention that this is a series that thrives on parallels and contrasts between characters and relationships between different characters.
The only parallel I see is they fought.
Sorry got to go.