I'd actually agree with a lot of what you said, plotting is OK for this VN. Except for the last sentence. If you're comparing this against other VN works this is one of the best.
This game is accessible in that sex is easy to get to but also paradoxically sex is treated as something that matters in this universe. The plot is simple but that's not the standout. The standout ability of this game is how it treats sex, again like it matters and affects people emotionally.
Firstly the standpoint piece of these game IMO which you neglected is the music and the tone of the renders that gives the entire game a depressing feel. Most games just rush past this. The tone is the backdrop for a game where sex is bought, sold, people are sexually abused, killed, the dominance stat, etc...what this game accomplishes is it's created a plausible expanded universe where sex operates at the center of it as a tool.
How many games have succeeded at this? 90% of games have varying levels of renders and writing but they will fail to portray a world in which sex functions frequently enough, but also seamlessly within the fabric of the world its set in, and written interestingly enough to titillate the reader. Not only does this game succeed at this, but instead of a contrived scenario like "man in a house with 3 sisters and his mom", this game goes out of its way to do (limited) world building to, again, help transport the reader into a world where sex is the capital that runs the town. This game is one of the best ever to do it.
