However, Peacock, who won 30 caps for England and Great Britain before retiring from the international game in 2012, is convinced McNamara remains the right man for the job after laying the foundations for success and believes the visit of New Zealand for a three-match test series next year can help him prove it.
"It's an exciting time for that team when you look how many players are world class and how many are on the cusp of being world class," said Peacock.
"That's testimony to the environment that Steve McNamara and his coaching staff have created over the last five years to enable players to reach their potential.
"As a coach, you've got to get the performance right and I feel this team is as competitive with the southern hemisphere sides as any we've had over the last 15 years.
"I came back from the 2008 World Cup with a sense that we were a million miles away and also when I looked at the team in 2010 I thought England were some way away from beating New Zealand and Australia.
"Now that clearly isn't the case any more.
"We were 20 seconds away from a World Cup final and a fingertip away from beating Australia. There's a fine line, we're not a million miles away."