One point that the authors give extensive time to is the idea of compromises and dilemmas in teaching. They warn against relying too much on process and losing touch with what's going on with your students:
"Too much reliance on a recipe leads to other problems. It can close off thoughtful responsiveness of the teacher-designer -- empathy! -- in the false belief that any well-thought-out plan must, of necessity, work, and if it doesn't, it must be the students' fault." (p. 267)
I probably narrowly missed falling into this trap myself, to be honest: my "xenobiology expedition" idea would have been great for students of a certain stripe, but it just isn't likely to work with students who are as grounded in the brutal realities of inner-city life as mine are going to be. I'll have to meet them where they're at and do my best to make the content as relevant as possible -- and, even then, keep in mind the need to keep getting feedback and making adjustments on the fly. As the authors make clear throughout the chapter, good design is an ongoing, iterative process -- one that's never really finished, because each crop of students is different.