There are two distinct markets that Apple needs to address:
1. Middle and High School students: School districts are purchasing Chromebooks like crazy, so Apple needs to get back into this market. Chromebooks sell for about $300-$400, so iPad Pros won't compete. The challenge of making the low cost iPad the education solution is that Apple's Smart Keyboard ($150) and Pencil ($100) are just too damn expensive for this market. Also, I am not sure it would be practical to have middle school kids carry delicate $100 Pencils around their campus.
2. College Students and Common Laptop Consumers: The MacBook Air has been the everyday workhorse laptop of choice for college students and many consumers. However, this model is long overdue for an update, and the other Apple MacBooks (rMB and MBP) are just not price competitive or suitable (limited ports, no MagSafe, inferior battery life, faulty keyboard) for the college/consumer market. So, Apple needs to create a college/consumer laptop alternative that is attractively priced, capable, and doesn't significantly cut into sales of their other MacBooks.
We will just have to see how this goes.