I often see people substituting "leader" for "elder" in talking about NT church offices/functions. And this is just one of many instances (when I read christianese) where I'm never quite sure what they mean. Maybe it's simply a manner of speaking, but I think it betrays a common mindset that only certain people are qualified to "lead". That may be true in the military, but I think it's very false in other walks of life.
Oversight is parenting, which often involves watching and waiting. Leadership is setting a course for action and then taking said action, which is something parents and teens ought to work out together. Oversight is coaching. Leadership is doing. The second string linebacker can demonstrate leadership on his high school team in a number of ways, but the coaches bear the brunt of responsibility for the game and the team - before, during and after each play, in and outside the locker room, on and off the field.
Leadership is something anyone can contribute during an ongoing group effort. Coaches "lead" less and less overtly as a team grows, matures and learns how to execute its proper functions together. In a coaching situation, the balance of leadership shifts back and forth between coaches and players. But oversight is the constant resolve of a tireless caretaker. His concern is not merely to accomplish a task, but to develop competent task-accomplishers on every part of the team.
I may or may not have seen it much in my day, but I believe New Testament Eldering is service oriented in a much more behind the scenes way than we usually hear about. By the way, I don't find any value in equating the terms "lead" and "serve". That's purely apologetic semantics, if you ask me.
Actual leadership is not necessarily just by example. It includes reminding others of that which we have all agreed to, sometimes (gasp) even with verbal imperative commands. It means making suggestions about specific activities we can all follow along and participate in. Leadership can be charging once more into the breach, when you just so happen to get followed. It can also be standing up to exclaim, "Let's all charge once more into the breach. What do you say?"
Oversight is a precious commodity healthy churches are blessed to have, usually given in larger supply to certain individuals who have learned how to deal with problems graciously in the spirit. Leadership is just as precious in a whole different way. Without Leadership, people sit around and do absolutely nothing. Leadership is vital to movement of the body and the spirit.
Oversight is best recognized (even better when not-often-acclaimed) as being granted to a select number of experienced folks. Leadership is that which every joint can and - for God's Own Sake - really ought to supply.
Elders most certainly can and should lead, perhaps more often in some seasons than others. When they've done their job best is when we might see them the least. But Elders are not the same thing as Leaders, and therefore we should not equate the two terms. It is not only a matter of linguistic precision. It is a matter of setting our sights on a healthier, more holistic, more scriptural benchmark for the functional development of the members of the Body of Christ.
Oh, okay. Fine. Be militaristic in your institutionalism and exclude non-elders from leading. But at the very least, don't equate these two terms when talking about Elders in the New Testament. That's anachronistic. It may be other things, too. ;-)