If your characters are interchangeable, forgettable and one dimensional you will have trouble getting readers to read much of your book.
Readers meet a character and watch, waiting for something to happen. If we don’t care enough about the character because they are just a placeholder, we put the book down.
Plots happen to someone and if that someone is an undeveloped element and not a character, we don’t care.
I was reading a book set during the French Revolution - it had a strong plot and a few interesting characters, but others were rather flat. I read on because one character was a young nobleman with republican views who joined the revolution. The author killed off a lot of interesting characters, but I kept reading because this guy had a problem and I wanted to see how it was resolved. I cared about him. She killed him off too and I put the book down - no one left I cared to follow.
Memorable characters are either hard work to create or they come as inspiration. 999
They fuel even the most plot driven story - they are the reason the reader turns the page.
My piece is a character driven thriller and before I started writing it, I spent weeks thinking about two characters (one is minor, yet pivotal). I had a clear plot and my characters and I started writing. My characters reached a point where they diverged from the plot, essentially telling me they had a better idea. They did and the book went in a direction I had not foreseen.
My point is, had I held to my original plot, forced it to play out as I had planned, I would have 80k words of a generic novel that I would probably not want to read - at least, not twice. Following my characters, I have a much longer work that I am proud of, enjoy reading, and is fun to write.
I have no idea how it will end, suspect I will slip the original plot in sometime in the future and trust my characters to tell the tale. It is their story, I am just writing it. 846