Accepting the validity of the assumption -- that most administrators are eclectic -- then the statement would refer to the fact that most administrators or managers have a certain amount of experience through seniority and training that enables them to bring a greater range of vision to the task at hand. "Eclectic" simply means that someone has a broad range of knowledge, skills and experiences from which that individual can draw in analyzing a problem and coming up with a solution. An eclectic individual has many interests and is generally considered well-rounded. He or she is not mentally or intellectually limited in his or her approach to a subject by virtue of limited education or experience.
The assumption underlying the question is highly questionable, as it is not uncommon to find adminstrators and managers who are anything but eclectic. To the extent that one is fortunate enough to have an eclectic administrator on the payroll, it is definitely a positive asset. Such individuals are more likely, and more capable of, thinking "outside the box" in analyzing a certain situation, because they have a greater capacity to incorporate into their though processes a greater range of information.