I agree the number of girls is maybe a little too high, but they won't all be part of the core harem right away, some of them will take a long time to come in, and the story will have developed a lot by that point.
But to answer the question: no, girls won't be made optional. Doing so would introduce crazy amounts of branching when you consider how interwoven all of the girls' stories and interactions are, it would probably half the speed at which I put content out right away, and get worse and worse over time. So fundamentally it will always remain a kinetic novel with a few insignificant flavour choices in sex scenes.