It was probably a mistake to carry on after last season. It was common knowledge that this would be his final season and maybe players on longer contracts don't have the same 'spark' if they know someone else will determine their future. The same thing seemed to affect Martin O'Neill at Forest, who also let it be known that he was only there for a limited time.
What a managerial career though. Warnock maybe wasn't liked by everyone in the game, but anyone who didn't respect his ability and achievements must be a fool. He'll always be welcome at Meadow Lane.