Just to throw my two cents in: I'm not surprised or upset that people hate Rachel, I deliberately wrote her to be hated. Some of the LIs start out being unlikeable, and then slowly grow into different people; it's a recurrent theme with a number of them, though Rachel is the most extreme example. It may be hard to believe now that she's the most popular, but early on people hated Sarah and wanted me to get rid of her. Same with Catherine, Vicky, and Hannah. Go back far enough in this thread and you'll find pages and pages of people hating Hannah.
So I'm not gonna remove Rachel, or change my plans for her. I might not be able to redeem her in the eyes of her most ardent haters, perhaps I'm not a talented enough writer to pull it off, but I'm certainly gonna try, as that was why I created the character in the first place.
As for significant choices, such as being able to choose characters: they're simply not possible with how I write the story. Granted, I haven't actually read a ton of other AVNs, but the ones I have, tend to keep the storylines of the individual girls somewhat separated to get around the need to rewrite a completely alternate universe after every player decision.
Just imagine, as an example, if the player had the option to reject Lucy. With how integrated she is into every event, every story beat, every piece of character development that happens in the MC and the other girls as a consequence of knowing her - all of that would be gone. Their entire character arcs and personalities would have to change to account for her absence. The same is true of each LI after Lucy, as they get more and more integrated into the story and the lives of the other characters; and eventually it would be the same for Rachel, too.