Before he left they were 3rd in the League with games in hand. We had two of the Leagues top ten leading goalscorers, and had turned in a superb performance against a team currently 5th in the Premier League. So Jim's team , with Jim in charge, was doing pretty well.
Apart from the first game after he left the same "bunch" look as if they don't know how to score a goal.
Of course there are plenty of managers who can build a successful team, but at present we have gone backwards rapidly.