This is something that I've gone back & forth on for years.
When Dea was in 4th grade, we tried having a list of required reading for her. This did not work out for us. First, my kids are not the kind of kids who will do things just because someone told them to. If it doesn't make sense to them, they will question it. So, every required book was met with a barrage of questions. Why did you choose this one? Does it have some sort of significance? What about it makes you believe that I will enjoy it? Why this book from this author and not another of his works? Is this related to what we're studying in some subject?
In addition to the questioning of every selection, she would get it into her head that should would not enjoy the book. That would taint her reading experience. So, since she is an avid and strong reader, I decided not to push the assigned reading at that time. Every once in a while, she gets into a rut and sticks to just one or two genres. This is generally because she is getting book recommendations from friends, and they stick to just one or two genres. At those times, I will suggest books of other genres, that I think she would enjoy. She still fights my recommendations sometimes, but mostly sees that I'm not bad at choosing books she'll like. Right now, she is doing the Exploring Genres reading challenge with Jay & me. Though she needs to get better at letting me know what books she's reading, so I can list her choices for the challenge. The challenge makes sure that she is reading a variety of works.
Since she is doing her High School English courses, we are doing required reading again. When choosing books for her English courses, I try to balance books that I believe are important & everyone should read with books that I think she'll enjoy. I won't force her to read a book that she won't enjoy unless it has a strong significance and there are no other books, covering the same issues & themes, that she would enjoy more. I don't feel bound to the lists of books that would be required in public high schools. I've actually rewritten the list of books for her English courses several times, since she kept reading books on her own, that were on the list.
With Jay, I thought about trying required reading for 3rd grade. I have changed my mind, though. He's quite good about reading books that I suggest that are related to our studies. He is also an avid & strong reader. He would likely respond, much like his sister, with an interrogation about book selections. He is also doing the Exploring Genres challenge, which is making sure he reads from a variety of genres & authors. So, at this time, I see no reason to require certain books.
Honestly, I understand requiring certain books for high school courses. However, prior to high school courses, I only see the point in certain circumstances:
A) If the child is a reluctant reader who will not read unless forced
B) If the child is a struggling reader & the book selections are carefully made
C) If the child sticks strictly to a limited number of genres or authors and more subtle methods (suggesting, reading challenges, making a deal with them about how many of their choices can be their usual fare & how many must be something new, etc.) have not worked
In those situations, I can see required reading being useful. Those don't describe us, though. So, I think I'll leave required reading to high school courses and just let them enjoy their free reading.