But you can't put a guy with absolutely no experience as sports director on that position in the club as big as Barca. Usual way is to find some position in youth teams and then judge if that person has the potential to develop into something that first team could use. Or maybe give him a scout position on some market. Definitely don't give him a power to play with hundreds of millions and basically steer the direction of the whole club.
Exactly! Being a great player, a legend of a club does not mean will be a great coach or sport director. Very few cases can have double successes like that, I can list a few: J. Cruyff, F. Beckenbauer, Zagallo (Brazil), D. Zoff (Italy), Guardiola (Spain) and a few others. Mostly average or below average players become great coaches, managers like Mourinho, Wenger, Ferguson, etc.
Barca made many mistakes from transfer to their club management (like appointment for E. Abidal as a sport director) and this season all of those bad mistakes were reflected and uncovered by Bayern.