I think the telling thing is that things really began to slide once Dooley ceased to take a fully active part in the club's affairs. ie when he retired from the position of football club chairman after we got promoted to the premier league. And it seemed to have been around this time that the McCabe/Warnock relationship became less amicable.
Re Heath and Bruce, I always thought they were really McDonald's preferred appointments even though they may have been 'officially' given the position by others. Dooley's autobiography cedrtainly gives this impression with regard to Heath. He says that immediately after McDonald's departure just before the Port Vale game when he went to see him, Heath was on edge "and obviously felt the sudden turn of events had left him exposed and vulnerable."