Just by looking at the first pages of the serialization turned me off from this whole thing. The oneshot made me interested in the concept of both of them growing more sexual with one another while trying to keep their feelings and desires in check, but just knowing there's more people involved with all this makes me feel I've seen the same shit done in like 90 different doujins, just that in those they also get to fuck.
Just a slow, soft burn of how things start and then progress more and more, with their lives being affected over time, until they just can't manage to control themselves properly, getting closer and closer to that taboo, until something or other that serves as a climax happens, WITH ONLY BOTH OF THEM AS PARTNERS, would serve as something more interesting. Otherwise, the other characters disperse the "tension" (or something to that effect? suspense?) one's supposed to feel about how the main ones are going to deal and how the story is going to progress, and serving as plain wish fulfillment. Not saying the alternative wouldn't also be wish fulfillment, but at least it is more interesting wish fulfillment than something I can already get in who knows how many different flavors and even less restrictions than with this.