Pretty much agree with everything here. This game is walking it's own path. It doesn't really fit into the common categories that we are accustomed to. Many games these days tries to follow the same paths laid out before them. College slice of life stuff, harem builders, NTR, corruption, incest romance tropey games, trainers, etc etc.I may be reading too much into the MC's inner monologues, but I think how 'good' a guy the MC is will be one of the main themes of the game. He chose to work at the Carnation Club, but he did that before he knew much about how the place worked. It's also not clear just badly he needed that money Chuck offered him.
It's obviously a Faustian deal in retrospect, but that still doesn't tell us whether the MC was a good guy who made a mistake or a bad guy who no longer needs to act otherwise. We'll decide that ourselves based on how we make the MC respond to the situations he finds himself in. That's my guess, anyway.
I do think that makes the game a bit niche, though. People who flat out hate dark themes have plenty of games where the MC isn't helping bad people exploit desperate girls. People who find dark themes a guilty pleasure would prefer games that don't put quite as much emphasis on the guilty part. It's only those of us who either revel in the darkness or relish the chance to deliberately refute it that get something unique out of this game.
It's somewhat similar with your point about sharing the LIs. NTR (or anything remotely approaching it) is already a bit of a niche; it's a very polarizing topic and the majority dislike it. This game has enough of it to be a hard pass for everyone who despises NTR, but there's not enough to be a slam dunk for those who love NTR, either.
Rosalind isn't in debt to a bank, she's in debt to organized crime. The penalty for non-payment to them is bad enough that I don't consider her participation voluntary. Veronica's would be... except for the detail that the only reason she's in so much debt is that Samson sabotaged her business specifically to force her into the contest. How is that meaningfully different from extortion?
Here, we have a rather dark premise of a powerful organization taking advantage of desperate women. However, it's not so simple when you look deeper into it. Lesser writers might have taken this set up and gone for the low hanging fruit of corruption/slave/domination type of story (I am not saying those are bad, it's my preferred tags actually). With Pale Carnations, we see so much depth in all the characters and how the story unfolds. The beauty of this script is that all characters are behaving in a believable manner in accordance to their motivations, personality, and circumstances. This is why it's so convincing. While the main plot line is on the dark side, there is a surprising amount of heart at it's core. There are some lowkey humor in it too.
I don't think there is a single cookie cutter character that fits snugly into a cliche.
Ian is a damn good friend if there ever was one, but obviously he has a rather cynical view of women. There are moments where his humanity shows through like when he interacts with MC's mom or when he talks about the priority being the carnations' well being. Doesn't mean he will pass on the bukkake ceremony or something.
Boss Lady is a femme fatale and is extremely ruthless. But she has shown some masochistic streaks during one of the games. Did she though? How much of it was an act? Maybe it was entirely faked. Maybe it was real, and it was a hint at some possibilities way down the road. She's a hard one to read and that is her strength.
The father of the biker chick is clearly evil at first glance. He leverages her mom's medical bills to make her work there. What's his angle? It's a really horrible thing to do to his daughter, but he does seem to care about her well being in his own way. He watches her concert incognito. Is he just keeping tabs or does he just want to see her doing what she likes? Is making her work there some misguided attempts to bring her back into his life after walking away?
Rosalind is the most sympathetic character here. She seems a bit timid at first, but she has a surprisingly strong resolve to make a better life for her daughter. She even tries to seduce the MC to get an advantage (something she is clearly not accustomed to doing). But is it all an act? We know for sure shes agreeing to be MC's plaything as a means to an end. However, she is clearly enjoying it to some extent. Maybe even just subconsciously.
I could go on about every character really. The way the MC is handled is especially commendable. The MC's voice is a hard one to get right in a choice heavy game because there is usually some common text that plays in between choices. In many games, the darker choices are wildly out of sync with how the MC usually acts... cough.. Radiant.. cough. I didn't notice any such problem here. A large part of it is because the MC's baseline persona is presented as neutral/grey, which is something most games with good/evil choices fails at accomplishing. Another reason is that there are no truly dark or sinister choices (at least so far). He can indulge and take advantage, but it is in line with his job description. All the choices are believable for any normal person to make given the circumstances. He isn't suddenly having a burst of psychopathy like some other games. Most importantly, the MC is a competently normal person, which makes him a great avatar. Lot's of games feature some "average joe" as a bumbling idiot way out of his depth. Others might show a full on sociopath who may or may not be aware of his condition. Some games offer the God MC that rolled 18 in all stats. Here, we see an actual average guy who has his issues but tries to make optimal choices and doesn't buckle under pressure.
As for the sharing and stuff, it probably takes a bit of refined taste to fully appreciate this. It's not a typical story revolving around the MC. The MC is just a cog in the wheel just like everyone else.
I must sound like a fangay after this text dump