From Cristina del Rivero:
"What, if anything, does that last criterion [i.e., refinement of collections] accomplish? Arguably nothing since as drafted it is completely open to abuse and will neither ensure possession in the future (donors' big fear) nor guarantee public access to artworks held in 'public trust' (i.e., remedying the incomprehensible reality that collections are largely in storage while museums are increasing on the verge of financial collapse and closure)."
Background here.
UPDATE: Lee Rosenbaum concedes that ""refinement of collections' leaves a lot of wiggle room" and that "one person's 'redundancy' is another person's 'depth,'" but still she describes the new (now passed) rules as "allow[ing] museums to dispose of works from their collections only if at least one of the following 10 criteria is met." The emphasis on "only" is hers, but I can't imagine any possible deaccessioning that cannot be described as "refining the collection." Isn't it true, almost by definition, of any sale by a museum? It's just more smoke and mirrors.
UPDATE 2: The New York Times reporting on the subject continues to misleadingly suggest that, until this latest set of rules was adopted, museums could use sales proceeds for operating expenses. That's not true.