I was always taught that a course syllabus was a contract between a professor and a student. A dynamic syllabus sounds like a make-it-up-as-you-go-along kind of contract, which is very unsettling from a student perspective. Making it linkable is great, but also just a fancy version of a 3-4 page document. I completely disagree that assignments should be thought of as dynamic or changable as we go along... A contract is a contract.