The elder arrangement was flawed from the very start and I'm not simply going back to 1971 when it was introduced. You need to hark back to the 1920s when J.F. Rutherford decided to appoint a "Service Director" in each congregation who would oversee the canvassing work. Then, in 1938 when a London congregation asked the WTS to appoint all its officers, power was taken away from the local congregations and transferred to Brooklyn. This is not to say that things were better beforehand. When congregations selected their own elders, many men shamelessly campaigned for the office, bribery of all kinds was all too common, and powerful cliques emerged which turned congregations into their own private fiefdoms. Those abuses are what led the London congregation to ask the WTS to step in.
When congregations were relatively small only three men were needed to manage their affairs. They and the circuit servant, as that traveling overseer was then known, kept a tight lid on things. The elder arrangement made it possible for more men to serve as different offices were created. At first, this infusion of "new blood" breathed life into many congregations and revitalized them. Individual publishers had several options for counseling and guidance and some men truly benefited from doing real shepherding work as elders. Others learned how to teach and speak when they served as Watchtower Study conductor and Theocratic Ministry School overseer. All the presiding overseer did was schedule public talks and chair the meetings of the servant body. Additionally, in those first years, no office was held permanently by one man. All the elders rotated through the various offices that were created to serve the congregation. This was to prevent the kind of dominance that had come about under the old elective elder and subsequent congregation servant arrangement.
But as with many things that are of purely human origin, corruption has set in. Most elders today have no idea how things worked back in the early 1970s and the Governing Body has taken great pains to keep them in the dark. That has been part and parcel of the strategy to completely transform the cult so that only oldtimers know how things once were and most of them have endorsed the changes as manifestations of "new light." However, not everyone has been deceived and more people are coming to the realization that holy spirit never has been, is not now, and never will be involved in the appointment of any of these men--from ministerial servant to Governing Body member--to the positions they hold.