In my 37 years of teaching high school English I went back and forth on this issue. Some thoughts:
The ideal setup is a curriculum with many electives so students can sort themselves. Maybe they want to take British Literature, which is difficult, or Contemporary Literature, which is more accessible to mediocre readers. I do think that students who want to take more difficult courses should be able to, and high-achieving students—who may be taking difficult math and science courses—should be able to take an English or history course that is interesting for them, even if it’s not so difficult.
I also think there should be catch-up courses for kids who have poor skills. A poor reader is not going to be able to read John Donne. He should be put into a saturation reading and writing program until his skills are at a level that he can take more mainstream classes.
What always chilled me were high schools with separate tracks that kids pretty much got stuck in.