I mostly agree with Peter Greene's on the malign take on what we now call "competency-based assessment." He sees it more as the return of "outcome based assessment" 20 years later, whereas I see the standards-based era as a continuous evolutionary thread of the the same theme, with slight rebranding.
The underlying problem is that there is no real theory underpinning the action. I mean, people have probably written some theory about the nature of standards, competencies, etc., but it is not cited or used in K-12 education. Nobody actually refers to it. You can never definitively say that someone's competency list is incorrectly designed, for example, because there is no recognized authority on the question of competency design.
Beyond that, there's not much alternative theory. That is, nobody really wants to defend assessing learning by Carnegie units instead of directly tracking student learning, although one can probably empirically show that it works well enough in various high performing systems around the world, despite its apparent logical flaws.
Put another way, when has anyone decided not to send their child to an elite prep school because it tracked graduation requirements by course credit, not competency?
When it comes to the administration of justice, I am in favor of legal systems based on written law, with the caveat that the efficacy of the system is entirely dependent on the quality and fairness of the laws, not to mention the many details of their implementation. Being generically in favor of outcome/standards/competency/skill-based education is equivalent to being in favor of a law-based justice system. Yes, of course! But if you don't have a good set of laws, based on a foundation of legal theory and scholarship, it doesn't get you far, and even then, the success of the system is entirely dependent on administration and implementation. In this metaphor, we're trying to write "laws," or competencies, without a constitution, law library, legal scholars or firm theory of law.