I know HBIC likes to talk about that game he plays (Football Manager), if you handed HBIC the DOF role and asked him to sign 7 players based around that game predicting players potential, I would expect he would have signed Eriksen (the only actual success).
But yes, its not just us, yet I view Arnesen (until he ****ed off) as the only proper DOF we have had. Comolli did sign talented players, but again, signing players that are highly rated because you're in a position to sign them, doesn't mean he should be given credit for his ability to spot players as Utd wanted Bale, Modric was highly sought after, Berba was highly regarded, list goes on but none of these players where rare finds. The DOF has to work with the manager but the only time we had a DOF/Manager where you could say "great partnership" was Arnesen/Jol, while all I remember from Comolli/Jol was Jol appearing to not sign the type of player he wanted, rather work with the type of player handed to him.