Do you not think that the reason managers, like Warnock, win 8 promotions and managers, like Pep, Fergie, Mourinho and other successful managers at the top end of the game, haven't won all those promotions is that Warnock isn't quite good enough for the top division? Pep is not going to win 8 promotions as he's not going to spend all that time in lower divisions. Warnock has had to because top flight teams have not fancied giving him a go.
I'm going to go out on a limb here, but I wouldn't even compare Warnock to Graham Taylor.