I cannot agree with this. The main job of the farm director is to build a strong organization of minor league managers, coaches, and roving instructors. He needs to be good at evaluating tools, because these are a measure of how fast a prospect is developing and if the minor league staff is doing an adequate job in developing him -- the tools speak to the players ultimate potential and the farm director needs to assess if and how rapidly he is moving to achieve that potential and if not, then why not. Was a big flaw, physical or character, missed in scouting the player? Is the development staff not developing him properly. Properly assessing this is the key not only to overhauling development staff and mentoring those who remain, but also to determining when to move a guy up a level, who to recommend for 40-man roster, who to recommend for trade high. The farm director is not a teacher of prospects directly. GM skills seem a huge plus for the position.
You'd like to keep a good guy for 5 years or more, but if he does a good job for 3 years and leaves with a strong minor league staff in place, then this is a big plus. It's been a long time since we had a farm director whom we could say that about. Hiring from the outside is a plus. Who knows, he could even be the Phillies next Dombrowski or Fuld.