This is not a new problem. And while it’s true clergy really need to manage time off, many sources will tell you that burnout is -not- the result of overwork per se, but of unrealistic expectations– sometimes on the part of the congregation, but perhaps even more on the part of the pastor. See this (about 20 years old!) article:
“The essence of the problem, however, is the clash between expectations and reality. Clergy are often put on a pedestal – by others, and by themselves. Many of these expectations just can’t be met. We try to please, but may either become too goal-oriented for our people, or else too accommodating to their spiritual ‘slackness’. ‘Strongly goal-oriented ministers will almost inevitably experience more frustration than process-oriented ones’ (Hart). We are working with volunteers, many of whom aren’t there when the work is unrewarding. And we’re stuck with each other – pastors have not hired most of the lay people they work with.