Duff had one good season not playing for Souness, Jansen has had none (for different reasons). Dunn hasn't been the same since Souness stole 5 million from the Big Club for him. Everyone says he was lucky inheriting them. Ask BFS how "lucky" he was getting Duff and Bruce how "lucky" he was to get Dunn.
To be fair, they were both really good managers for us. Sparky just had better timing in leaving.
Edit: For those that look at Yorke and DePedro and laugh, ask Jim/John and LeChuck, respectively, what they thought of the players before they stunk up the joint.