As a reading teacher I can tell you that in 3rd/4th there usually is not a "required reading" list. Research shows that if kids have free choice in their reading, they will enjoy reading more, read more books, and the more they read, the better their reading will get. If there is required reading, it is what is included in the district's reading curriculum. Otherwise independent reading is free choice.
In our district at 3rd/4th grade, kids are really working on genre expansion, vocabulary expansion, and building stamina. They are expected to read a chapter book a week. Our students have free choice in what they read during their independent reading time. They do need to show evidence of having to read a variety of genres. They are expected to read from a genre list including History, Social Studies, Biography/ Autobiography, Science, Adventure stories, Contemporary / Realistic Fiction, Horror (that is age appropriate), Traditional Tales, Fables, Folktales, Myths, Drama, Poetry, Journals, Speeches, Tall Tales, Poetry, Media (newspapers and magazines). Graphic novels would also be allowed. Never are they expected to read specific titles for independent reading. Teachers may give them examples of books in each genre, but the kids pick what they want to read.
They also learn Greek and Latin root words, prefixes, and suffixes as a way of building their vocabulary. Some teachers have kids keep "word collections" of words that they want to start using in their every day speech and writing.
They are also working on making inferences about their reading and using higher order thinking skills to deepen their understanding of the texts they are reading. (Google higher order thinking skills for examples of activities and sample questions.) They are learning how to make connections, compare and contrast, analyze, predict, think critically, etc.
I do not work with a single teacher who still has students do book reports. They have students keep response journals where they interact with the text. Some teachers will give students a question to answer about the book they are reading. For example: "What problem does the main character have to solve? What do you think the character will do to solve the problem?" "What words does the author use to describe the setting/characters?" "From what you know of the main character so far, would you want to be friends with him/her? Why or why not? What evidence is there in the text to support your response?" Some teachers might have students write 5 paragraph papers about a book, but they aren't quite the same as the old book reports we did as kids. It is more about the writing process for a 5 point essay than it is about the book.
I wouldn't count on the volume of homework increasing with a change of schools. Research has shown that if homework is just busy work, it isn't necessarily beneficial for student learning. More and more schools are taking the stance that homework should be minimal and intentional. Lots of homework does not necessarily equal a "good education."
As a former gifted and talented teacher I can tell you that in elementary schools GT services are very limited. Most GT service (if it is there) is a pull out program that happens just once or twice a week for 30-45 minutes. Classroom teachers do what they can to provide enrichment for advanced learners, but the reality is that they also have limited time and resources. Two of my colleagues who teach 4th grade recently spent an entire day working on developing enrichment activities just for math. Unfortunately until kids reach middle school and sometimes even high school, parents have to take the step to find enrichment opportunities.
Our daughter is in 1st grade. We have already stepped into doing multiplication at home with her. We also have many science experiment kits, social studies and art books. We do a lot of enrichment at home. But, it isn't forced on her. We provide the opportunity for her and she decides what she is ready for. I have seen too many advanced kids (and keep in mind that advanced does not always equal gifted and talented) who are burnt out on school by the time they reach 5th grade because their parents have pushed them so hard.
My advice, take it or leave it, is to share your concerns with your son's teacher, but also realize that you will have to take some steps for providing enrichment for your son. That may be through summer camp experiences, community ed classes, or things that you do together at home. Start teaching him division. Find a robotics group or a Lego science group. More than likely there are some home school groups in your area who will have those kinds of groups. Maybe you can find a computer programming class for him. And let him read what he wants to read. Start a word collection of interesting words. Take family field trips to museums, nature centers, state parks, historical sites, theater productions, and concerts. Monopolize on your son's interests. The kids who are best educated are the kids who have teachers and parents who work together to teach them.