He was out of his depth at Crusaders RL - edging Nobby out of his coaching role. Nobby took a team of no-hopers to the top 8 of Super League - within a season virtually the same team were bottom of the league. Lots of pundits said the Crusaders job was too early for Harris.
He allegedly spent a fortune when Wales RL coach, players put on weight and didn't play to their potential in the World Cup, losing all their games and not progressing past the pool stage.
He again replaced Nobby at Salford and took time to establish himself. Perhaps he's never really had the team he build himself but former players were vocal about his lack of management skills... so no real surprise that he may be on his way out.
As others have said - a good second-in-command.