Backwards design is a method of approaching course design by starting "at the end" and working your way through the course backwards, so to speak. The basic idea is that you should begin the process by asking the following four questions (from Ken Bain's What the Best College Teachers Do):
1) What should my students be able to do intellectually, physically, or emotionally as a result of their learning? 2) How can I best help and encourage them to develop those abilities and the habits of mind to use them? 3) How can my students and I best understand the nature, quality, and progress of their learning? 4) How can I evaluate my efforts to foster that learning? (Bain 49)
Fair enough. It seems good to me to begin designing a course by figuring out how people should be different after having interacted with the course. This comports with design advice in other areas. How should players feel at the end of a game? How should listeners feel at the end of a play, podcast, or song? How should readers update their beliefs at the end of an article or book? How should people interact with your park bench, tea kettle, headphones, traffic intersection, or whatever? How should the world be different after you've made your thing?
My concern about backwards design is that it presumes that we can predict how students will change during the semester. Maybe the thing that will change for them after interacting with your course is that they will have been evicted, or their kid will be sick, or they'll lose a parent. Maybe the most important thing about the semester won't be your course. My point isn't that life events are outside of your control or that they are unpredictable. My point is that you can't predict how your course will interact with the rest of a student's life.
Obviously as instructors we should consider who we are teaching, what their lives are like, and the material and social circumstances of their lives as they participate in the class. But what I don't think we can predict with any accuracy is how the course will effect them, either in the short term or the long term. This is why I think that the best approach to course design accommodates a largely individualized approach to education.