Something which seems to escape us is that the spiritual gift of the undershepherd is "pastor" while the office is that of elder/bishop. A plurality of elders is a necessity, because no pastor can truly minister to more than perhaps two dozen people effectively (one-on-one), and the principle of plurality was strongly entrenched since the time of Moses, because he went to Lord and told Him that he could not handle the burden on his own. A single pastor church puts a huge burden on one man and also robs all believers of their functions as Royal Priests.
I agree with all the points raised by Undead. One of the reasons we do not have a Scriptural pattern of church leadership is because of Bible School/Seminary training having become a "qualification" for pastor/elder/bishop. If you trace this to its roots, it goes back to Roman Catholicism through the Reformation Churches, and the Catholic priesthood had already robbed believers of their high and holy calling as King-Priests. Until this teaching is restored, we will have unbiblical church leadership in evangelical churches.