It seems that ‘vacuous’ is being used here to indicate questions-remain-unanswered/instructions-are-not-explicit-enough? All high-level/aspirational objectives leave room for interpretation. The question, How is our service distinctive to GW as opposed to any old university will help all staff strive for a higher goal. That’s as vacuous as a question like, What do you want your life to have looked like on your deathbed, ie not at all IMO