Johnson's side were knocked out at the quarter-final stage on Saturday after a 19-12 defeat by France in Auckland.
"For the management I think it's down to Martin Johnson to, as he said, consider his position," Guscott told BBC Sport.
The ex England centre also believes his one-time teammate has had trouble replicating the success he had as a player since taking the managerial role.
"As a player he was all about winning and as a coach you'd like to think he was the same," he added. "In that regard he's come up short."