Dave Hoffman has a post with the catchy title--Solum on the Need for Opinions. Here's a taste:
It is not novel to point out that law school overemphasizes the role of judicial opinions as a percentage of what constitutes "law". The first-year common law method approach is at the root of this bias, and no doubt leads to the heuristic that law = reasoning = legitimacy. But many legal rules are simple commands (statutes; police instructions) unadorned by justifications. Indeed, asking a police officer for the reason behind an order is likely to engender suspicion, at the least. Even as a description of the normative legitimacy of judicial product, the focus on reasons seems to me to be an artifact of appellate thinking. Appeals courts are all about reasons, possibly because they lack the intimate acquaintance with the instruments of force (jailers, marshals) that accompany district court life.
My research focuses on district courts in part because as a clerk for a district judge, I realized that "we" were creating a great deal of law without giving any explanation, let alone full-fledged, blue-booked, opinions.