I would love to see some sort of a student-paced accessibility block or wall option that we could add in to lessons. Here's why: I may have a PDF of a story on one page, and questions over it on the next page. I would want students to be able to move back and forth between the story and questions, but not be able to proceed in student-paced mode to see the answers and explanations that come after it! Or, if students are more advanced, they could have an optional enrichment slide to complete after the main activity while others finish up, but they cannot progress further in the lesson without the teacher taking the class there. If we could drop in a "block" or "wall" or something, this could allow students to navigate before and up to the wall, but they cannot proceed past it without the teacher moving the lesson into the next "realm."